diff --git a/src/main/java/com/example/log4u/domain/diary/controller/DiaryController.java b/src/main/java/com/example/log4u/domain/diary/controller/DiaryController.java
index 9cb281de..c117b200 100644
--- a/src/main/java/com/example/log4u/domain/diary/controller/DiaryController.java
+++ b/src/main/java/com/example/log4u/domain/diary/controller/DiaryController.java
@@ -18,7 +18,7 @@
 import com.example.log4u.domain.diary.SortType;
 import com.example.log4u.domain.diary.dto.DiaryRequestDto;
 import com.example.log4u.domain.diary.dto.DiaryResponseDto;
-import com.example.log4u.domain.diary.service.DiaryService;
+import com.example.log4u.domain.diary.facade.DiaryFacade;
 
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
@@ -30,7 +30,7 @@
 @Slf4j
 public class DiaryController {
 
-	private final DiaryService diaryService;
+	private final DiaryFacade diaryFacade;
 
 	@GetMapping("/users/{userId}")
 	public ResponseEntity<PageResponse<DiaryResponseDto>> getDiariesByUserId(
@@ -39,7 +39,7 @@ public ResponseEntity<PageResponse<DiaryResponseDto>> getDiariesByUserId(
 		@RequestParam(required = false) Long cursorId,
 		@RequestParam(defaultValue = "12") int size
 	) {
-		PageResponse<DiaryResponseDto> response = diaryService.getDiariesByCursor(customOAuth2User.getUserId(),
+		PageResponse<DiaryResponseDto> response = diaryFacade.getDiariesByCursor(customOAuth2User.getUserId(),
 			targetUserId, cursorId, size);
 
 		return ResponseEntity.ok(response);
@@ -50,7 +50,7 @@ public ResponseEntity<Void> createDiary(
 		@AuthenticationPrincipal CustomOAuth2User customOAuth2User,
 		@Valid @RequestBody DiaryRequestDto request
 	) {
-		diaryService.saveDiary(customOAuth2User.getUserId(), request);
+		diaryFacade.createDiary(customOAuth2User.getUserId(), request);
 		return ResponseEntity.status(HttpStatus.CREATED).build();
 	}
 
@@ -63,7 +63,7 @@ public ResponseEntity<PageResponse<DiaryResponseDto>> searchDiaries(
 		@RequestParam(defaultValue = "6") int size
 	) {
 		return ResponseEntity.ok(
-			diaryService.searchDiariesByCursor(keyword, sort, cursorId, size)
+			diaryFacade.searchDiariesByCursor(keyword, sort, cursorId, size)
 		);
 	}
 
@@ -72,7 +72,7 @@ public ResponseEntity<DiaryResponseDto> getDiary(
 		@AuthenticationPrincipal CustomOAuth2User customOAuth2User,
 		@PathVariable Long diaryId
 	) {
-		DiaryResponseDto diary = diaryService.getDiary(customOAuth2User.getUserId(), diaryId);
+		DiaryResponseDto diary = diaryFacade.getDiary(customOAuth2User.getUserId(), diaryId);
 		return ResponseEntity.ok(diary);
 	}
 
@@ -82,16 +82,16 @@ public ResponseEntity<Void> modifyDiary(
 		@PathVariable Long diaryId,
 		@Valid @RequestBody DiaryRequestDto request
 	) {
-		diaryService.updateDiary(customOAuth2User.getUserId(), diaryId, request);
+		diaryFacade.updateDiary(customOAuth2User.getUserId(), diaryId, request);
 		return ResponseEntity.ok().build();
 	}
 
 	@DeleteMapping("/{diaryId}")
-	public ResponseEntity<?> deleteDiary(
+	public ResponseEntity<Void> deleteDiary(
 		@AuthenticationPrincipal CustomOAuth2User customOAuth2User,
 		@PathVariable Long diaryId
 	) {
-		diaryService.deleteDiary(customOAuth2User.getUserId(), diaryId);
+		diaryFacade.deleteDiary(customOAuth2User.getUserId(), diaryId);
 		return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
 	}
 }
diff --git a/src/main/java/com/example/log4u/domain/diary/facade/DiaryFacade.java b/src/main/java/com/example/log4u/domain/diary/facade/DiaryFacade.java
new file mode 100644
index 00000000..01a2ab4d
--- /dev/null
+++ b/src/main/java/com/example/log4u/domain/diary/facade/DiaryFacade.java
@@ -0,0 +1,127 @@
+package com.example.log4u.domain.diary.facade;
+
+import java.util.List;
+
+import org.springframework.data.domain.Slice;
+import org.springframework.stereotype.Component;
+
+import com.example.log4u.common.dto.PageResponse;
+import com.example.log4u.domain.diary.SortType;
+import com.example.log4u.domain.diary.dto.DiaryRequestDto;
+import com.example.log4u.domain.diary.dto.DiaryResponseDto;
+import com.example.log4u.domain.diary.entity.Diary;
+import com.example.log4u.domain.diary.service.DiaryService;
+import com.example.log4u.domain.like.service.LikeService;
+import com.example.log4u.domain.map.service.MapService;
+import com.example.log4u.domain.media.entity.Media;
+import com.example.log4u.domain.media.service.MediaService;
+
+import lombok.RequiredArgsConstructor;
+
+@Component
+@RequiredArgsConstructor
+public class DiaryFacade {
+
+	private final DiaryService diaryService;
+	private final MediaService mediaService;
+	private final MapService mapService;
+	private final LikeService likeService;
+
+	/**
+	 * 다이어리 생성 use case
+	 * <ul><li>호출 과정</li></ul>
+	 * 1. mediaService: 섬네일 이미지 url 생성<br>
+	 * 2. diaryService: 다이어리 생성<br>
+	 * 2. mediaService: 해당 다이어리의 이미지 저장<br>
+	 * 3. mapService: 해당 구역 카운트 증가
+	 * */
+	public void createDiary(Long userId, DiaryRequestDto request) {
+		String thumbnailUrl = mediaService.extractThumbnailUrl(request.mediaList());
+		Diary diary = diaryService.saveDiary(userId, request, thumbnailUrl);
+		mediaService.saveMedia(diary.getDiaryId(), request.mediaList());
+		mapService.increaseRegionDiaryCount(request.location().latitude(), request.location().longitude());
+	}
+
+	/**
+	 * 다이어리 삭제 use case
+	 * <ul><li>호출 과정</li></ul>
+	 * 1. diaryService: 다이어리 검증
+	 * 2. mediaService: 해당 다이어리 이미지 삭제<br>
+	 * 3. diaryService: 다이어리 삭제<br>
+	 * */
+	public void deleteDiary(Long userId, Long diaryId) {
+		Diary diary = diaryService.getDiaryAfterValidateOwnership(userId, diaryId);
+		mediaService.deleteMediaByDiaryId(diaryId);
+		diaryService.deleteDiary(diary);
+	}
+
+	/**
+	 * 다이어리 수정 use case
+	 * <ul><li>호출 과정</li></ul>
+	 * 1. diaryService: 다이어리 검증<br>
+	 * 2. mediaService: 해당 다이어리 이미지 삭제<br>
+	 * 3. diaryService: 다이어리 수정
+	 * */
+	public void updateDiary(Long userId, Long diaryId, DiaryRequestDto request) {
+		Diary diary = diaryService.getDiaryAfterValidateOwnership(userId, diaryId);
+		if (request.mediaList() != null) {
+			mediaService.updateMediaByDiaryId(diary.getDiaryId(), request.mediaList());
+		}
+		String newThumbnailUrl = mediaService.extractThumbnailUrl(request.mediaList());
+		diaryService.updateDiary(diary, request, newThumbnailUrl);
+	}
+
+	/**
+	 * 다이어리 단건 조회 use case
+	 * <ul><li>호출 과정</li></ul>
+	 * 1. diaryService: 공개 범위 검증 후 다이어리 조회<br>
+	 * 2. likeService: 좋아요 기록 조회<br>
+	 * 3. mediaService: 해당 다이어리의 이미지 조회<br>
+	 * 4. 모든 정보 조합 후 dto 변환 해 반환
+	 * */
+	public DiaryResponseDto getDiary(Long userId, Long diaryId) {
+		Diary diary = diaryService.getDiaryAfterValidateAccess(userId, diaryId);
+		boolean isLiked = likeService.isLiked(userId, diaryId);
+		List<Media> media = mediaService.getMediaByDiaryId(diary.getDiaryId());
+		return DiaryResponseDto.of(diary, media, isLiked);
+	}
+
+	/**
+	 * 다이어리 목록 조회 By UserId use case
+	 * <ul><li>호출 과정</li></ul>
+	 * 1. diaryService : DiaryResponseDto Slice 객체 조회<br>
+	 * 2. nextCursor 정보 생성<br>
+	 * 3. PageResponse 조합 후 반환
+	 * */
+	public PageResponse<DiaryResponseDto> getDiariesByCursor(
+		Long userId,
+		Long targetUserId,
+		Long cursorId,
+		int size
+	) {
+		Slice<DiaryResponseDto> dtoSlice = diaryService.getDiaryResponseDtoSlice(userId, targetUserId, cursorId, size);
+		// 다음 커서 ID 계산
+		Long nextCursor = !dtoSlice.isEmpty() ? dtoSlice.getContent().getLast().diaryId() : null;
+		return PageResponse.of(dtoSlice, nextCursor);
+	}
+
+	/**
+	 * 다이어리 검색 목록 조회 By Cursor use case
+	 * <ul><li>호출 과정</li></ul>
+	 * 1. diaryService : DiaryResponseDto Slice 객체 조회<br>
+	 * 2. nextCursor 정보 생성<br>
+	 * 3. PageResponse 조합 후 반환<br>
+	 * */
+	public PageResponse<DiaryResponseDto> searchDiariesByCursor(
+		String keyword,
+		SortType sort,
+		Long cursorId,
+		int size
+	) {
+		Slice<DiaryResponseDto> dtoSlice = diaryService.searchDiariesByCursor(keyword, sort, cursorId, size);
+		// 다음 커서 ID 계산
+		Long nextCursor = !dtoSlice.isEmpty() ? dtoSlice.getContent().getLast().diaryId() : null;
+		return PageResponse.of(dtoSlice, nextCursor);
+	}
+
+}
diff --git a/src/main/java/com/example/log4u/domain/diary/service/DiaryService.java b/src/main/java/com/example/log4u/domain/diary/service/DiaryService.java
index 145fa97b..b8c2aff0 100644
--- a/src/main/java/com/example/log4u/domain/diary/service/DiaryService.java
+++ b/src/main/java/com/example/log4u/domain/diary/service/DiaryService.java
@@ -22,7 +22,6 @@
 import com.example.log4u.domain.diary.repository.DiaryRepository;
 import com.example.log4u.domain.follow.repository.FollowRepository;
 import com.example.log4u.domain.like.repository.LikeRepository;
-import com.example.log4u.domain.map.service.MapService;
 import com.example.log4u.domain.media.entity.Media;
 import com.example.log4u.domain.media.service.MediaService;
 
@@ -37,23 +36,17 @@ public class DiaryService {
 	private final DiaryRepository diaryRepository;
 	private final FollowRepository followRepository;
 	private final MediaService mediaService;
-	private final MapService mapService;
 	private final LikeRepository likeRepository;
 
 	// 다이어리 생성
 	@Transactional
-	public void saveDiary(Long userId, DiaryRequestDto request) {
-		String thumbnailUrl = mediaService.extractThumbnailUrl(request.mediaList());
-		Diary diary = diaryRepository.save(
-			DiaryRequestDto.toEntity(userId, request, thumbnailUrl)
-		);
-		mediaService.saveMedia(diary.getDiaryId(), request.mediaList());
-		mapService.increaseRegionDiaryCount(request.location().latitude(), request.location().longitude());
+	public Diary saveDiary(Long userId, DiaryRequestDto request, String thumbnailUrl) {
+		return diaryRepository.save(DiaryRequestDto.toEntity(userId, request, thumbnailUrl));
 	}
 
 	// 다이어리 검색
 	@Transactional(readOnly = true)
-	public PageResponse<DiaryResponseDto> searchDiariesByCursor(
+	public Slice<DiaryResponseDto> searchDiariesByCursor(
 		String keyword,
 		SortType sort,
 		Long cursorId,
@@ -66,17 +59,12 @@ public PageResponse<DiaryResponseDto> searchDiariesByCursor(
 			cursorId != null ? cursorId : Long.MAX_VALUE,
 			PageRequest.of(0, size)
 		);
-
-		Slice<DiaryResponseDto> dtoSlice = mapToDtoSlice(diaries);
-
-		// 다음 커서 ID 계산
-		Long nextCursor = !dtoSlice.isEmpty() ? dtoSlice.getContent().getLast().diaryId() : null;
-
-		return PageResponse.of(dtoSlice, nextCursor);
+		return mapToDtoSlice(diaries);
 	}
 
 	// 다이어리 상세 조회
 	@Transactional(readOnly = true)
+	@Deprecated(since = "파사드 패턴 도입으로 인해 불필요해짐", forRemoval = false)
 	public DiaryResponseDto getDiary(Long userId, Long diaryId) {
 		Diary diary = findDiaryOrThrow(diaryId);
 
@@ -89,43 +77,27 @@ public DiaryResponseDto getDiary(Long userId, Long diaryId) {
 
 	// 다이어리 목록 (프로필 페이지)
 	@Transactional(readOnly = true)
-	public PageResponse<DiaryResponseDto> getDiariesByCursor(Long userId, Long targetUserId, Long cursorId, int size) {
+	public Slice<DiaryResponseDto> getDiaryResponseDtoSlice(Long userId, Long targetUserId, Long cursorId, int size) {
 		List<VisibilityType> visibilities = determineAccessibleVisibilities(userId, targetUserId);
-
 		Slice<Diary> diaries = diaryRepository.findByUserIdAndVisibilityInAndCursorId(
 			targetUserId,
 			visibilities,
 			cursorId != null ? cursorId : Long.MAX_VALUE,
 			PageRequest.of(0, size)
 		);
-
-		Slice<DiaryResponseDto> dtoSlice = mapToDtoSlice(diaries);
-
-		Long nextCursor = !dtoSlice.isEmpty() ? dtoSlice.getContent().getLast().diaryId() : null;
-
-		return PageResponse.of(dtoSlice, nextCursor);
+		return mapToDtoSlice(diaries);
 	}
 
 	// 다이어리 수정
 	@Transactional
-	public void updateDiary(Long userId, Long diaryId, DiaryRequestDto request) {
-		Diary diary = findDiaryOrThrow(diaryId);
-		validateOwner(diary, userId);
-
-		if (request.mediaList() != null) {
-			mediaService.updateMediaByDiaryId(diary.getDiaryId(), request.mediaList());
-		}
-
-		String newThumbnailUrl = mediaService.extractThumbnailUrl(request.mediaList());
+	public void updateDiary(Diary diary, DiaryRequestDto request, String newThumbnailUrl) {
 		diary.update(request, newThumbnailUrl);
+		diaryRepository.save(diary);
 	}
 
 	// 다이어리 삭제
 	@Transactional
-	public void deleteDiary(Long userId, Long diaryId) {
-		Diary diary = findDiaryOrThrow(diaryId);
-		validateOwner(diary, userId);
-		mediaService.deleteMediaByDiaryId(diaryId);
+	public void deleteDiary(Diary diary) {
 		diaryRepository.delete(diary);
 	}
 
@@ -173,7 +145,7 @@ private void validateOwner(Diary diary, Long userId) {
 		}
 	}
 
-	// 다이어리 목록 조회 시 권한 체크
+	// 다이어리 목록 조회 시 권한 체크(공개 정책)
 	private List<VisibilityType> determineAccessibleVisibilities(Long userId, Long targetUserId) {
 		if (userId.equals(targetUserId)) {
 			return List.of(VisibilityType.PUBLIC, VisibilityType.PRIVATE, VisibilityType.FOLLOWER);
@@ -186,6 +158,20 @@ private List<VisibilityType> determineAccessibleVisibilities(Long userId, Long t
 		return List.of(VisibilityType.PUBLIC);
 	}
 
+	// 파사드 패턴에서 사용할 검증 로직(소유 검증)
+	public Diary getDiaryAfterValidateOwnership(Long diaryId, Long userId) {
+		Diary diary = findDiaryOrThrow(diaryId);
+		validateOwner(diary, userId);
+		return diary;
+	}
+
+	// 파사드 패턴에서 사용할 검증 로직(공개 범위 검증)
+	public Diary getDiaryAfterValidateAccess(Long diaryId, Long userId) {
+		Diary diary = findDiaryOrThrow(diaryId);
+		validateDiaryAccess(diary, userId);
+		return diary;
+	}
+
 	// 다이어리 상세 조회 시 권한 체크
 	private void validateDiaryAccess(Diary diary, Long userId) {
 		if (diary.getVisibility() == VisibilityType.PRIVATE) {
diff --git a/src/main/java/com/example/log4u/domain/like/service/LikeService.java b/src/main/java/com/example/log4u/domain/like/service/LikeService.java
index 4f368cb7..873aef2a 100644
--- a/src/main/java/com/example/log4u/domain/like/service/LikeService.java
+++ b/src/main/java/com/example/log4u/domain/like/service/LikeService.java
@@ -1,7 +1,5 @@
 package com.example.log4u.domain.like.service;
 
-import java.util.Optional;
-
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -52,4 +50,9 @@ private void validateDuplicateLike(Long userId, Long diaryId) {
 			throw new DuplicateLikeException();
 		}
 	}
+
+	// 파사드 패턴에서 사용할 함수
+	public boolean isLiked(Long userId, Long diaryId) {
+		return likeRepository.existsByUserIdAndDiaryId(userId, diaryId);
+	}
 }
diff --git a/src/test/java/com/example/log4u/domain/diary/service/DiaryServiceTest.java b/src/test/java/com/example/log4u/domain/diary/service/DiaryServiceTest.java
index 25882dc0..56a5fafb 100644
--- a/src/test/java/com/example/log4u/domain/diary/service/DiaryServiceTest.java
+++ b/src/test/java/com/example/log4u/domain/diary/service/DiaryServiceTest.java
@@ -1,12 +1,11 @@
 package com.example.log4u.domain.diary.service;
 
 import static org.assertj.core.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.ArgumentMatchers.*;
 import static org.mockito.BDDMockito.*;
 
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Optional;
 
 import org.junit.jupiter.api.DisplayName;
@@ -19,7 +18,6 @@
 import org.springframework.data.domain.Slice;
 import org.springframework.data.domain.SliceImpl;
 
-import com.example.log4u.common.dto.PageResponse;
 import com.example.log4u.domain.diary.SortType;
 import com.example.log4u.domain.diary.VisibilityType;
 import com.example.log4u.domain.diary.dto.DiaryRequestDto;
@@ -30,56 +28,50 @@
 import com.example.log4u.domain.diary.repository.DiaryRepository;
 import com.example.log4u.domain.follow.repository.FollowRepository;
 import com.example.log4u.domain.like.repository.LikeRepository;
-import com.example.log4u.domain.map.service.MapService;
 import com.example.log4u.domain.media.entity.Media;
 import com.example.log4u.domain.media.service.MediaService;
 import com.example.log4u.fixture.DiaryFixture;
 import com.example.log4u.fixture.MediaFixture;
 
 @ExtendWith(MockitoExtension.class)
-public class DiaryServiceTest {
+class DiaryServiceTest {
 
 	@Mock
 	private DiaryRepository diaryRepository;
 
-	@Mock
-	private LikeRepository likeRepository;
-
 	@Mock
 	private FollowRepository followRepository;
 
 	@Mock
 	private MediaService mediaService;
 
-	@InjectMocks
-	private DiaryService diaryService;
-
 	@Mock
-	private MapService mapService;
-
-	private static final int CURSOR_PAGE_SIZE = 12;
+	private LikeRepository likeRepository;
 
-	private static final int SEARCH_PAGE_SIZE = 6;
+	@InjectMocks
+	private DiaryService diaryService;
 
 	@Test
-	@DisplayName("다이어리 생성 성공")
-	void saveDiary() {
+	@DisplayName("다이어리 생성 - 성공")
+	void saveDiary_success() {
 		// given
 		Long userId = 1L;
-		DiaryRequestDto request = DiaryFixture.createDiaryRequestDtoFixture();
+		String thumbnailUrl = "https://example.com/thumb.jpg";
 
-		String thumbnailUrl = "https://example.com/image1.jpg";
-		Diary diary = DiaryFixture.createPublicDiaryFixture(1L, userId);
+		DiaryRequestDto request = DiaryFixture.createDiaryRequestDtoFixture();
 
-		given(mediaService.extractThumbnailUrl(request.mediaList())).willReturn(thumbnailUrl);
-		given(diaryRepository.save(any(Diary.class))).willReturn(diary);
+		given(diaryRepository.save(any(Diary.class))).willAnswer(invocation -> invocation.getArgument(0));
 
 		// when
-		diaryService.saveDiary(userId, request);
+		Diary result = diaryService.saveDiary(userId, request, thumbnailUrl);
 
 		// then
-		verify(mediaService).saveMedia(eq(diary.getDiaryId()), eq(request.mediaList()));
-		verify(mapService).increaseRegionDiaryCount(request.location().latitude(), request.location().longitude());
+		assertThat(result.getUserId()).isEqualTo(userId);
+		assertThat(result.getTitle()).isEqualTo(request.title());
+		assertThat(result.getContent()).isEqualTo(request.content());
+		assertThat(result.getThumbnailUrl()).isEqualTo(thumbnailUrl);
+
+		verify(diaryRepository).save(any(Diary.class));
 	}
 
 	@Test
@@ -98,40 +90,24 @@ void searchDiaries() {
 			eq(keyword),
 			eq(List.of(VisibilityType.PUBLIC)),
 			eq(sort),
-			eq(Long.MAX_VALUE),
+			anyLong(),
 			any(PageRequest.class)
 		)).willReturn(diarySlice);
 
-		Map<Long, List<Media>> mediaMap = new HashMap<>();
-		for (Diary diary : diaries) {
-			mediaMap.put(diary.getDiaryId(), List.of(
-				MediaFixture.createMediaFixture(diary.getDiaryId() * 10, diary.getDiaryId())
-			));
-		}
-
-		given(mediaService.getMediaMapByDiaryIds(anyList())).willReturn(mediaMap);
-
 		// when
-		PageResponse<DiaryResponseDto> result = diaryService.searchDiariesByCursor(keyword, sort, cursorId, size);
+		Slice<DiaryResponseDto> result = diaryService.searchDiariesByCursor(keyword, sort, cursorId, size);
 
 		// then
-		assertThat(result.list()).hasSize(3);
-		assertThat(result.pageInfo().hasNext()).isFalse();
-
-		assertThat(result.list()).allSatisfy(diary -> {
-			assertThat(diary.title().contains(keyword) || diary.content().contains(keyword))
-				.as("다이어리 제목 또는 내용에 키워드 '%s'가 포함되어야 합니다.", keyword)
-				.isTrue();
-		});
-
-		DiaryResponseDto firstDiary = result.list().get(0);
-		assertThat(firstDiary.diaryId()).isEqualTo(diaries.get(0).getDiaryId());
-		assertThat(firstDiary.title()).isEqualTo(diaries.get(0).getTitle());
-		assertThat(firstDiary.content()).isEqualTo(diaries.get(0).getContent());
-		assertThat(firstDiary.userId()).isEqualTo(diaries.get(0).getUserId());
-		assertThat(firstDiary.visibility()).isEqualTo(diaries.get(0).getVisibility().name());
-		assertThat(firstDiary.weatherInfo()).isEqualTo(diaries.get(0).getWeatherInfo().name());
-		assertThat(firstDiary.mediaList()).hasSize(1);
+		assertEquals(6, result.getSize());
+		assertFalse(result.hasNext());
+
+		verify(diaryRepository).searchDiariesByCursor(
+			eq(keyword),
+			eq(List.of(VisibilityType.PUBLIC)),
+			eq(sort),
+			anyLong(),
+			any(PageRequest.class)
+		);
 	}
 
 	@Test
@@ -247,71 +223,62 @@ void getDiariesByCursor() {
 		int size = 12;
 
 		List<Diary> diaries = DiaryFixture.createDiariesWithIdsFixture(3);
-		Slice<Diary> diarySlice = new SliceImpl<>(diaries, PageRequest.of(0, CURSOR_PAGE_SIZE), false);
+		Slice<Diary> diarySlice = new SliceImpl<>(diaries, PageRequest.of(0, size), true);
 
+		// mocking
+		given(followRepository.existsByInitiatorIdAndTargetId(userId, targetUserId)).willReturn(true);
 		given(diaryRepository.findByUserIdAndVisibilityInAndCursorId(
 			eq(targetUserId),
-			eq(List.of(VisibilityType.PUBLIC)),
+			anyList(),
 			eq(cursorId),
 			any(PageRequest.class)
 		)).willReturn(diarySlice);
 
-		Map<Long, List<Media>> mediaMap = new HashMap<>();
-		for (Diary diary : diaries) {
-			mediaMap.put(diary.getDiaryId(), List.of(
-				MediaFixture.createMediaFixture(diary.getDiaryId() * 10, diary.getDiaryId())
-			));
-		}
-
-		given(mediaService.getMediaMapByDiaryIds(anyList())).willReturn(mediaMap);
-
 		// when
-		PageResponse<DiaryResponseDto> result = diaryService.getDiariesByCursor(userId, targetUserId, cursorId, size);
+		Slice<DiaryResponseDto> result = diaryService.getDiaryResponseDtoSlice(userId, targetUserId, cursorId, size);
 
 		// then
-		assertThat(result.list()).hasSize(3);
-		assertThat(result.pageInfo().hasNext()).isFalse();
+		assertThat(result).hasSize(3);
+		assertThat(result.hasNext()).isTrue();
+		verify(diaryRepository).findByUserIdAndVisibilityInAndCursorId(
+			eq(targetUserId),
+			anyList(),
+			eq(cursorId),
+			any(PageRequest.class)
+		);
 	}
 
 	@Test
 	@DisplayName("다이어리 수정 성공")
 	void updateDiary() {
 		// given
-		Long userId = 1L;
-		Long diaryId = 1L;
+		Diary diary = mock(Diary.class);
 		DiaryRequestDto request = DiaryFixture.createPublicDiaryRequestDtoFixture();
 
-		Diary diary = DiaryFixture.createPublicDiaryFixture(diaryId, userId);
 		String newThumbnailUrl = "https://example.com/public.jpg";
 
-		given(diaryRepository.findById(diaryId)).willReturn(Optional.of(diary));
-		given(mediaService.extractThumbnailUrl(request.mediaList())).willReturn(newThumbnailUrl);
-
 		// when
-		diaryService.updateDiary(userId, diaryId, request);
+		diaryService.updateDiary(diary, request, newThumbnailUrl);
 
 		// then
-		verify(mediaService).updateMediaByDiaryId(eq(diaryId), eq(request.mediaList()));
-		assertThat(diary.getTitle()).isEqualTo(request.title());
-		assertThat(diary.getContent()).isEqualTo(request.content());
-		assertThat(diary.getThumbnailUrl()).isEqualTo(newThumbnailUrl);
+		verify(diary).update(request, newThumbnailUrl); // update 메서드 호출 확인
+		verify(diaryRepository).save(diary); // save 호출 확인
 	}
 
 	@Test
-	@DisplayName("다이어리 수정 실패 - 작성자가 아닌 경우")
+	@DisplayName("다이어리 수정 실패(검증 로직 실패) - 작성자가 아닌 경우")
 	void updateDiary_notOwner() {
 		// given
 		Long userId = 1L;
 		Long authorId = 2L;
 		Long diaryId = 1L;
-		DiaryRequestDto request = DiaryFixture.createPublicDiaryRequestDtoFixture();
 
 		Diary diary = DiaryFixture.createPublicDiaryFixture(diaryId, authorId);
 
 		given(diaryRepository.findById(diaryId)).willReturn(Optional.of(diary));
 
 		// when & then
-		assertThatThrownBy(() -> diaryService.updateDiary(userId, diaryId, request))
+		assertThatThrownBy(() -> diaryService.getDiaryAfterValidateOwnership(diaryId, userId))
 			.isInstanceOf(OwnerAccessDeniedException.class);
 	}
 
@@ -324,18 +291,15 @@ void deleteDiary() {
 
 		Diary diary = DiaryFixture.createPublicDiaryFixture(diaryId, userId);
 
-		given(diaryRepository.findById(diaryId)).willReturn(Optional.of(diary));
-
 		// when
-		diaryService.deleteDiary(userId, diaryId);
+		diaryService.deleteDiary(diary);
 
 		// then
-		verify(mediaService).deleteMediaByDiaryId(diaryId);
 		verify(diaryRepository).delete(diary);
 	}
 
 	@Test
-	@DisplayName("다이어리 삭제 실패 - 작성자가 아닌 경우")
+	@DisplayName("다이어리 삭제전 소유자 검증  - 작성자가 아닌 경우")
 	void deleteDiary_notOwner() {
 		// given
 		Long userId = 1L;
@@ -346,8 +310,8 @@ void deleteDiary_notOwner() {
 
 		given(diaryRepository.findById(diaryId)).willReturn(Optional.of(diary));
 
-		// when & then
-		assertThatThrownBy(() -> diaryService.deleteDiary(userId, diaryId))
+		// when & then  (서비스 검증로직)
+		assertThatThrownBy(() -> diaryService.getDiaryAfterValidateOwnership(userId, diaryId))
 			.isInstanceOf(OwnerAccessDeniedException.class);
 	}