diff --git a/src/main/java/com/kimgreen/backend/domain/AuditEntity.java b/src/main/java/com/kimgreen/backend/domain/AuditEntity.java
index 0920ed7..874af6f 100644
--- a/src/main/java/com/kimgreen/backend/domain/AuditEntity.java
+++ b/src/main/java/com/kimgreen/backend/domain/AuditEntity.java
@@ -19,18 +19,20 @@
 public class AuditEntity {
 
     @CreatedDate
-    private String createdAt;
+    private LocalDateTime createdAt;
     @LastModifiedDate
-    private String modifiedAt;
+    private LocalDateTime modifiedAt;
 
     @PrePersist
     public void prePersist() {
-        this.createdAt = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
+        String formattedDate = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
+        this.createdAt = LocalDateTime.parse(formattedDate,DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
         this.modifiedAt = this.createdAt;
     }
 
     @PreUpdate
     public void onUpdate() {
-        this.modifiedAt = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
+        String formattedDate = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
+        this.modifiedAt = LocalDateTime.parse(formattedDate,DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
     }
  }
diff --git a/src/main/java/com/kimgreen/backend/domain/notification/dto/NotificationResponseDto.java b/src/main/java/com/kimgreen/backend/domain/notification/dto/NotificationResponseDto.java
index f6da5a2..7a43636 100644
--- a/src/main/java/com/kimgreen/backend/domain/notification/dto/NotificationResponseDto.java
+++ b/src/main/java/com/kimgreen/backend/domain/notification/dto/NotificationResponseDto.java
@@ -13,7 +13,7 @@
 @Getter
 public class NotificationResponseDto {
     private Long postId;
-    private String createdAt;
+    private LocalDateTime createdAt;
     private String content;
 
     public static NotificationResponseDto getDto(Notification notification) {