diff --git a/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/controller/ApiV1SpaceController.java b/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/controller/ApiV1SpaceController.java
index 5be227f7..d3be1c2c 100644
--- a/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/controller/ApiV1SpaceController.java
+++ b/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/controller/ApiV1SpaceController.java
@@ -173,7 +173,7 @@ public RsData<ResBodyForSpaceListPage> getAllSpaces(
             return new SpaceInfo(
                     space.getId(),
                     space.getName(),
-                    space.getThumbnailUrl(),
+                    space.getThumbnailUrl() == null ? "" : space.getThumbnailUrl(),
                     membership.getAuthority(),
                     memberInfos
             );
diff --git a/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/service/SpaceService.java b/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/service/SpaceService.java
index cc9c464b..d75fba40 100644
--- a/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/service/SpaceService.java
+++ b/src/main/java/org/tuna/zoopzoop/backend/domain/space/space/service/SpaceService.java
@@ -184,7 +184,7 @@ public void updateSpaceThumbnail(Integer spaceId, Member requester, MultipartFil
             //String fileName = "space-thumbnail/prefix/space_id.jpg";
             // S3 저장 시 파일 이름 고정 (덮어쓰기)
             String extension = StringUtils.getFilenameExtension(image.getOriginalFilename());
-            String fileName = "space-thumbnail/" + s3Prefix + "/space_" + spaceId + "." + extension;
+            String fileName = "space-thumbnail/" + s3Prefix + "space_" + spaceId + "." + extension;
             String baseImageUrl = s3Service.upload(image, fileName);
 
             // DB 용으로 현재 시간을 쿼리 파라미터에 추가 (캐시 무효화)