diff --git a/server/router/api/v1/memo_service.go b/server/router/api/v1/memo_service.go
index db6dd141e..16f5ad165 100644
--- a/server/router/api/v1/memo_service.go
+++ b/server/router/api/v1/memo_service.go
@@ -497,23 +497,7 @@ func (s *APIV1Service) DeleteMemo(ctx context.Context, request *v1pb.DeleteMemoR
 		}
 	}
 
-	if err = s.Store.DeleteMemo(ctx, &store.DeleteMemo{ID: memo.ID}); err != nil {
-		return nil, status.Errorf(codes.Internal, "failed to delete memo")
-	}
-
-	// Delete memo relation
-	if err := s.Store.DeleteMemoRelation(ctx, &store.DeleteMemoRelation{MemoID: &memo.ID}); err != nil {
-		return nil, status.Errorf(codes.Internal, "failed to delete memo relations")
-	}
-
-	// Delete related attachments.
-	for _, attachment := range attachments {
-		if err := s.Store.DeleteAttachment(ctx, &store.DeleteAttachment{ID: attachment.ID}); err != nil {
-			return nil, status.Errorf(codes.Internal, "failed to delete attachment")
-		}
-	}
-
-	// Delete memo comments
+	// Delete memo comments first (store.DeleteMemo handles their relations and attachments)
 	commentType := store.MemoRelationComment
 	relations, err := s.Store.ListMemoRelations(ctx, &store.FindMemoRelation{RelatedMemoID: &memo.ID, Type: &commentType})
 	if err != nil {
@@ -525,10 +509,9 @@ func (s *APIV1Service) DeleteMemo(ctx context.Context, request *v1pb.DeleteMemoR
 		}
 	}
 
-	// Delete memo references
-	referenceType := store.MemoRelationReference
-	if err := s.Store.DeleteMemoRelation(ctx, &store.DeleteMemoRelation{RelatedMemoID: &memo.ID, Type: &referenceType}); err != nil {
-		return nil, status.Errorf(codes.Internal, "failed to delete memo references")
+	// Delete the memo (store.DeleteMemo handles relation and attachment cleanup)
+	if err = s.Store.DeleteMemo(ctx, &store.DeleteMemo{ID: memo.ID}); err != nil {
+		return nil, status.Errorf(codes.Internal, "failed to delete memo")
 	}
 
 	return &emptypb.Empty{}, nil
diff --git a/store/memo.go b/store/memo.go
index afd71e29a..ce6cde28d 100644
--- a/store/memo.go
+++ b/store/memo.go
@@ -138,5 +138,22 @@ func (s *Store) UpdateMemo(ctx context.Context, update *UpdateMemo) error {
 }
 
 func (s *Store) DeleteMemo(ctx context.Context, delete *DeleteMemo) error {
+	// Clean up memo_relation records where this memo is either the source or target.
+	if err := s.driver.DeleteMemoRelation(ctx, &DeleteMemoRelation{MemoID: &delete.ID}); err != nil {
+		return err
+	}
+	if err := s.driver.DeleteMemoRelation(ctx, &DeleteMemoRelation{RelatedMemoID: &delete.ID}); err != nil {
+		return err
+	}
+	// Clean up attachments linked to this memo.
+	attachments, err := s.ListAttachments(ctx, &FindAttachment{MemoID: &delete.ID})
+	if err != nil {
+		return err
+	}
+	for _, attachment := range attachments {
+		if err := s.DeleteAttachment(ctx, &DeleteAttachment{ID: attachment.ID}); err != nil {
+			return err
+		}
+	}
 	return s.driver.DeleteMemo(ctx, delete)
 }