diff --git a/src/apis/admin.ts b/src/apis/admin.ts
index 5eb1580..f768098 100644
--- a/src/apis/admin.ts
+++ b/src/apis/admin.ts
@@ -7,6 +7,7 @@ const postReports = async (postReportRequest: PostReportRequest) => {
     return res;
   } catch (error) {
     console.error(error);
+    return null;
   }
 };
 
diff --git a/src/apis/notification.ts b/src/apis/notification.ts
index 869df0a..3453135 100644
--- a/src/apis/notification.ts
+++ b/src/apis/notification.ts
@@ -31,4 +31,15 @@ const patchReadNotificationAll = async () => {
   }
 };
 
-export { getTimeLines, patchReadNotification, patchReadNotificationAll };
+const getNotReadCount = async () => {
+  try {
+    const res = await client.get('/api/notifications/not-read');
+    if (!res) throw new Error('안 읽은 알림 수를 가져오는 도중 오류가 발생했습니다.');
+    console.log(res);
+    return res;
+  } catch (error) {
+    console.error(error);
+  }
+};
+
+export { getTimeLines, patchReadNotification, patchReadNotificationAll, getNotReadCount };
diff --git a/src/components/NotificationButton.tsx b/src/components/NotificationButton.tsx
new file mode 100644
index 0000000..0047067
--- /dev/null
+++ b/src/components/NotificationButton.tsx
@@ -0,0 +1,36 @@
+import { getNotReadCount } from '@/apis/notification';
+import { AlarmIcon } from '@/assets/icons';
+import useNotificationStore from '@/stores/notificationStore';
+import { useEffect } from 'react';
+import { Link } from 'react-router';
+import { twMerge } from 'tailwind-merge';
+
+export default function NotificationButton() {
+  const notReadCount = useNotificationStore((state) => state.notReadCount);
+  const setNotReadCount = useNotificationStore((state) => state.setNotReadCount);
+  const notReadStyle = twMerge(
+    `absolute -right-1 -bottom-1 flex h-3.5 w-3.5 items-center justify-center rounded-full bg-red-400 text-[8px] text-white`,
+    notReadCount >= 100 && 'w-4 h-4',
+  );
+
+  const handleGetNotReadCount = async () => {
+    const res = await getNotReadCount();
+    if (res?.status === 200) {
+      const updateNotReadCount: number = res.data.data.notReadCount;
+      setNotReadCount(updateNotReadCount);
+    }
+  };
+
+  useEffect(() => {
+    handleGetNotReadCount();
+  });
+
+  return (
+    <Link to="/mypage/notifications" className="relative">
+      {notReadCount > 0 && (
+        <div className={notReadStyle}>{notReadCount < 100 ? notReadCount : '99+'}</div>
+      )}
+      <AlarmIcon className="h-6 w-6 text-white" />
+    </Link>
+  );
+}
diff --git a/src/components/ReportModal.tsx b/src/components/ReportModal.tsx
index b4dd2c8..ce84c91 100644
--- a/src/components/ReportModal.tsx
+++ b/src/components/ReportModal.tsx
@@ -5,6 +5,7 @@ import { postReports } from '@/apis/admin';
 
 import ConfirmModal from './ConfirmModal';
 import TextareaField from './TextareaField';
+import useToastStore from '@/stores/toastStore';
 
 interface ReportModalProps {
   reportType: ReportType;
@@ -40,14 +41,16 @@ const ReportModal = ({ reportType, letterId, onClose }: ReportModalProps) => {
     else setPostReportRequest((cur) => ({ ...cur, reasonType: reason }));
   };
 
+  const setToastActive = useToastStore((state) => state.setToastActive);
+
   const handleSubmit = async () => {
     const res = await postReports(postReportRequest);
     if (res?.status === 200) {
-      alert('신고 처리되었습니다.');
+      setToastActive({ title: '신고가 접수되었습니다.', toastType: 'Success' });
       console.log(res);
       onClose();
-    } else if (res?.status === 409) {
-      alert('신고한 이력이 있습니다.');
+    } else {
+      setToastActive({ title: '신고한 이력이 있습니다.', toastType: 'Error' });
       onClose();
     }
   };
diff --git a/src/components/ToastItem.tsx b/src/components/ToastItem.tsx
index 2465e5b..75a459d 100644
--- a/src/components/ToastItem.tsx
+++ b/src/components/ToastItem.tsx
@@ -26,7 +26,7 @@ export default function ToastItem({ toastObj, index }: { toastObj: ToastObj; ind
 
   const animation = `toast-blink ${toastObj.time}s ease-in-out forwards`;
   const toastStyle = twMerge(
-    'fixed bottom-5 left-1/2 z-40 flex h-[40px] max-w-150 min-w-[300px] w-[100%] -translate-1/2 items-center justify-center rounded-lg caption-sb shadow-[0_1px_6px_rgba(200,200,200,0.2)]',
+    'fixed bottom-5 left-1/2 z-40 flex h-[40px] max-w-150 min-w-[300px] w-[80%] -translate-1/2 items-center justify-center rounded-lg caption-sb shadow-[0_1px_6px_rgba(200,200,200,0.2)]',
     TOAST_POSITION[toastObj.position],
     TOAST_DESIGN[toastObj.toastType].style,
   );
diff --git a/src/hooks/useServerSentEvents.tsx b/src/hooks/useServerSentEvents.tsx
index 1ad9850..a0b406b 100644
--- a/src/hooks/useServerSentEvents.tsx
+++ b/src/hooks/useServerSentEvents.tsx
@@ -4,15 +4,55 @@ import { useEffect, useRef } from 'react';
 import useAuthStore from '@/stores/authStore';
 import useToastStore from '@/stores/toastStore';
 import { useNavigate } from 'react-router';
+import useNotificationStore from '@/stores/notificationStore';
+import { getNewToken } from '@/apis/auth';
+
+interface MessageEventData {
+  title: string;
+  alarmType: AlarmType;
+}
 
 export const useServerSentEvents = () => {
+  let reconnect: number | undefined;
+
   const navigate = useNavigate();
+  const recallCountRef = useRef(1);
 
   const accessToken = useAuthStore((state) => state.accessToken);
+  const setAccessToken = useAuthStore((state) => state.setAccessToken);
   const sourceRef = useRef<EventSourcePolyfill | null>(null);
 
   const setToastActive = useToastStore((state) => state.setToastActive);
 
+  const incrementNotReadCount = useNotificationStore((state) => state.incrementNotReadCount);
+
+  const ALARM_TYPE: AlarmType[] = ['SENDING', 'LETTER', 'REPORT', 'SHARE', 'POSTED'];
+  const handleOnMessage = async (data: string) => {
+    const message: MessageEventData = await JSON.parse(data);
+    if (ALARM_TYPE.includes(message.alarmType)) {
+      incrementNotReadCount();
+      setToastActive({
+        toastType: 'Info',
+        title: message.title,
+        position: 'Top',
+        time: 5,
+        onClick: () => navigate('/mypage/notifications'),
+      });
+    }
+  };
+
+  // 토큰 재발급 함수
+  const callReissue = async () => {
+    try {
+      const response = await getNewToken();
+      if (response?.status !== 200) throw new Error('error while fetching newToken');
+      const newToken = response?.data.data.accessToken;
+      return setAccessToken(newToken);
+    } catch (e) {
+      return Promise.reject(e);
+    }
+  };
+
   useEffect(() => {
     if (!accessToken) {
       console.log('로그인 정보 확인불가');
@@ -32,23 +72,24 @@ export const useServerSentEvents = () => {
         );
 
         sourceRef.current.onmessage = (event) => {
-          console.log(event);
-          console.log('알림 수신');
-          setToastActive({
-            toastType: 'Info',
-            title: '새 알림이 도착했어요!',
-            position: 'Top',
-            time: 5,
-            onClick: () => navigate('/mypage/notifications'),
-          });
+          // console.log(event);
+          // console.log('알림 수신');
+          handleOnMessage(event.data);
         };
 
-        sourceRef.current.onerror = (error) => {
-          console.log(error);
-          console.log('에러 발생함');
+        sourceRef.current.onerror = () => {
+          // 에러 발생시 해당 에러가 45초를 넘어서 발생한 에러인지, 401에러인지 판단할 수 있는게 없어서 그냥 에러 발생하면 reissue 넣는걸로 때움
+          callReissue();
           closeSSE();
+          recallCountRef.current += 1;
+          console.log('SSE연결 에러 발생');
+
           // 재연결 로직 추가 가능
-          setTimeout(connectSSE, 5000); // 5초 후 재연결 시도
+          if (recallCountRef.current < 5) {
+            reconnect = setTimeout(connectSSE, 5000);
+          } else {
+            console.log('5회 이상 에러발생으로 구독기능 제거');
+          }
         };
       } catch (error) {
         console.error(error);
@@ -64,6 +105,7 @@ export const useServerSentEvents = () => {
   }, [accessToken]);
 
   const closeSSE = () => {
+    if (reconnect) clearTimeout(reconnect);
     sourceRef.current?.close();
     sourceRef.current = null;
   };
diff --git a/src/layouts/Header.tsx b/src/layouts/Header.tsx
index 8efa549..ae58d9c 100644
--- a/src/layouts/Header.tsx
+++ b/src/layouts/Header.tsx
@@ -1,20 +1,20 @@
 import { Link, useNavigate } from 'react-router';
 
-import { AlarmIcon, ArrowLeftIcon, PersonIcon } from '@/assets/icons';
+import { ArrowLeftIcon, PersonIcon } from '@/assets/icons';
+import NotificationButton from '@/components/NotificationButton';
 
 const Header = () => {
   // TODO: 뒤로 가기 버튼이 보이는 조건 추가
   // TODO: 스크롤 발생 시, 어떻게 보여져야 하는지
   const navigate = useNavigate();
+
   return (
     <header className="fixed top-0 z-40 flex h-16 w-full max-w-150 items-center justify-between p-5">
       <button onClick={() => navigate(-1)}>
         <ArrowLeftIcon className="h-6 w-6 text-white" />
       </button>
       <div className="flex items-center gap-3">
-        <Link to="/mypage/notifications">
-          <AlarmIcon className="h-6 w-6 text-white" />
-        </Link>
+        <NotificationButton />
         <Link to="/mypage">
           <PersonIcon className="h-6 w-6 text-white" />
         </Link>
diff --git a/src/pages/Home/components/HomeHeader.tsx b/src/pages/Home/components/HomeHeader.tsx
index 3c1db95..a1ea28f 100644
--- a/src/pages/Home/components/HomeHeader.tsx
+++ b/src/pages/Home/components/HomeHeader.tsx
@@ -1,14 +1,13 @@
 import { Link } from 'react-router';
 
-import { AlarmIcon, PersonIcon } from '@/assets/icons';
+import { PersonIcon } from '@/assets/icons';
+import NotificationButton from '@/components/NotificationButton';
 
 const HomeHeader = () => {
   return (
     <header className="fixed top-0 z-40 flex h-16 w-full max-w-150 items-center justify-end p-5">
       <div className="flex items-center gap-3">
-        <Link to="/mypage/notifications">
-          <AlarmIcon className="h-6 w-6 text-white" />
-        </Link>
+        <NotificationButton />
         <Link to="/mypage">
           <PersonIcon className="h-6 w-6 text-white" />
         </Link>
diff --git a/src/pages/Notifications/components/WarningModal.tsx b/src/pages/Notifications/components/WarningModal.tsx
index 4470eb3..3b6ea46 100644
--- a/src/pages/Notifications/components/WarningModal.tsx
+++ b/src/pages/Notifications/components/WarningModal.tsx
@@ -34,13 +34,7 @@ const WarningModal = ({ isOpen, reportContent, onClose }: WarningModalProps) =>
           <p className="caption-r mb-5 text-black">{`${divideContents[1]} 회`}</p>
 
           <h2 className="body-sb mb-1.5 text-gray-100">경고 규칙</h2>
-          <p className="caption-r text-black">
-            1회 경고: 주의 안내
-            <br />
-            2회 경고: 7일 동안 서비스 이용 제한
-            <br />
-            3회 경고: 서비스 이용 불가능
-          </p>
+          <p className="caption-r text-black">3회 경고: 서비스 이용 불가능</p>
         </div>
       </article>
     </ModalOverlay>
diff --git a/src/pages/Notifications/index.tsx b/src/pages/Notifications/index.tsx
index a3c0cdc..257453e 100644
--- a/src/pages/Notifications/index.tsx
+++ b/src/pages/Notifications/index.tsx
@@ -7,10 +7,14 @@ import PageTitle from '@/components/PageTitle';
 import NotificationItem from './components/NotificationItem';
 import WarningModal from './components/WarningModal';
 import SendingModal from './components/SendingModal';
+import useNotificationStore from '@/stores/notificationStore';
 
 const NotificationsPage = () => {
   const navigate = useNavigate();
 
+  const decrementNotReadCount = useNotificationStore((state) => state.decrementNotReadCount);
+  const setNotReadCount = useNotificationStore((state) => state.setNotReadCount);
+
   const [noti, setNoti] = useState<Noti[]>([]);
 
   const [isOpenWarningModal, setIsOpenWarningModal] = useState(false);
@@ -51,7 +55,8 @@ const NotificationsPage = () => {
     if (res?.status === 200) {
       setNoti((curNoti) =>
         curNoti.map((noti) => {
-          if (noti.timelineId === timelineId) {
+          if (noti.timelineId === timelineId && !noti.read) {
+            decrementNotReadCount();
             return { ...noti, read: true };
           }
           return noti;
@@ -73,6 +78,7 @@ const NotificationsPage = () => {
           return noti;
         });
       });
+      setNotReadCount(0);
     } else {
       console.log('모두 읽음처리 에러 발생');
     }
diff --git a/src/stores/notificationStore.ts b/src/stores/notificationStore.ts
new file mode 100644
index 0000000..0a789a5
--- /dev/null
+++ b/src/stores/notificationStore.ts
@@ -0,0 +1,25 @@
+import { create } from 'zustand';
+
+interface NotificationStore {
+  notReadCount: number;
+  incrementNotReadCount: () => void;
+  decrementNotReadCount: () => void;
+  setNotReadCount: (updateCount: number) => void;
+}
+const useNotificationStore = create<NotificationStore>((set) => ({
+  notReadCount: 0,
+  incrementNotReadCount: () =>
+    set((state) => ({
+      notReadCount: state.notReadCount + 1,
+    })),
+  decrementNotReadCount: () =>
+    set((state) => ({
+      notReadCount: state.notReadCount - 1,
+    })),
+  setNotReadCount: (updateCount) =>
+    set(() => ({
+      notReadCount: updateCount,
+    })),
+}));
+
+export default useNotificationStore;
diff --git a/src/types/notifications.d.ts b/src/types/notifications.d.ts
index 672864a..6c131a2 100644
--- a/src/types/notifications.d.ts
+++ b/src/types/notifications.d.ts
@@ -1,6 +1,8 @@
+type AlarmType = 'SENDING' | 'LETTER' | 'REPORT' | 'SHARE' | 'POSTED';
+
 interface Noti {
   timelineId: number;
-  alarmType: string;
+  alarmType: AlarmType;
   content: string | number;
   title: string;
   read: boolean;