diff --git a/src/main/java/kr/co/conceptbe/notification/app/NotificationService.java b/src/main/java/kr/co/conceptbe/notification/app/NotificationService.java
index 49e2212..bea34df 100644
--- a/src/main/java/kr/co/conceptbe/notification/app/NotificationService.java
+++ b/src/main/java/kr/co/conceptbe/notification/app/NotificationService.java
@@ -4,6 +4,7 @@
 import kr.co.conceptbe.auth.presentation.dto.AuthCredentials;
 import kr.co.conceptbe.idea.domain.Idea;
 import kr.co.conceptbe.idea.domain.event.CreatedIdeaEvent;
+import kr.co.conceptbe.idea.domain.persistence.IdeaRepository;
 import kr.co.conceptbe.notification_setting.domain.IdeaNotificationSetting;
 import kr.co.conceptbe.notification_setting.domain.repository.NotificationSettingRepository;
 import kr.co.conceptbe.member.exception.NotFoundAuthCredentialException;
@@ -26,6 +27,7 @@ public class NotificationService {
     private final NotificationRepository notificationRepository;
     private final NotificationSettingRepository notificationSettingRepository;
     private final NotificationTrigger notificationTrigger;
+    private final IdeaRepository ideaRepository;
 
     @Transactional(readOnly = true)
     public List<NotificationResponse> findAllNotifications(
@@ -60,7 +62,7 @@ public void readNotification(AuthCredentials auth, Long notificationId) {
                 .orElseThrow(
                         () -> new IllegalArgumentException("Not Found Notification ID : " + notificationId)
                 );
-        notification.read(memberId);
+        notification.read(memberId, ideaRepository::findById);
         notificationRepository.save(notification);
     }
 
diff --git a/src/main/java/kr/co/conceptbe/notification/app/dto/NotificationResponse.java b/src/main/java/kr/co/conceptbe/notification/app/dto/NotificationResponse.java
index 2ed237c..32ff97d 100644
--- a/src/main/java/kr/co/conceptbe/notification/app/dto/NotificationResponse.java
+++ b/src/main/java/kr/co/conceptbe/notification/app/dto/NotificationResponse.java
@@ -9,7 +9,8 @@ public record NotificationResponse(
         Long feedId,
         String title,
         String createAt,
-        List<String> badges
+        List<String> badges,
+        boolean isAlreadyRead
 ) {
 
     public static NotificationResponse from(IdeaNotification notification) {
@@ -22,7 +23,8 @@ public static NotificationResponse from(IdeaNotification notification) {
                 notification.getIdeaId(),
                 notification.getTitle(),
                 notification.getCreatedAt().toString(),
-                ideaBranches
+                ideaBranches,
+                notification.isAlreadyRead()
         );
     }
 
diff --git a/src/main/java/kr/co/conceptbe/notification/domain/IdeaNotification.java b/src/main/java/kr/co/conceptbe/notification/domain/IdeaNotification.java
index c917cbe..aeedbc5 100644
--- a/src/main/java/kr/co/conceptbe/notification/domain/IdeaNotification.java
+++ b/src/main/java/kr/co/conceptbe/notification/domain/IdeaNotification.java
@@ -1,6 +1,7 @@
 package kr.co.conceptbe.notification.domain;
 
 import jakarta.persistence.*;
+import java.util.Optional;
 import kr.co.conceptbe.common.entity.base.BaseTimeEntity;
 import kr.co.conceptbe.idea.domain.Idea;
 import kr.co.conceptbe.idea.domain.IdeaBranch;
@@ -104,10 +105,16 @@ private List<String> splitBadges(String badges) {
         return new ArrayList<>(List.of(badgesEach));
     }
 
-    public void read(Long memberId) {
+    public void read(Long memberId, Function<Long, Optional<Idea>> getIdea) {
         if (!memberId.equals(this.memberId)) {
             throw new IllegalArgumentException("다른 계정의 알림을 읽을 수 없습니다.");
         }
+
+        Optional<Idea> idea = getIdea.apply(this.ideaId);
+        if (idea.isEmpty()) {
+            throw new IllegalArgumentException("게시글을 찾을 수 없습니다.");
+        }
+
         isAlreadyRead = true;
     }