diff --git a/src/components/common/FlatPostCard.tsx b/src/components/common/FlatPostCard.tsx
index e57e07fa..77db98bb 100644
--- a/src/components/common/FlatPostCard.tsx
+++ b/src/components/common/FlatPostCard.tsx
@@ -170,7 +170,9 @@ const FlatPostCard = ({ post, hideUser }: PostCardProps) => {
             />
           </VLink>
           <div className="username">
-            <VLink to={`${velogUrl}`}>{post.user.profile.display_name}</VLink>
+            <VLink to={`${velogUrl}`}>
+              {post.user?.profile?.display_name ?? post.user.username}
+            </VLink>
           </div>
         </div>
       )}
diff --git a/src/components/common/PostCard.tsx b/src/components/common/PostCard.tsx
index f4f6a8eb..1befe891 100644
--- a/src/components/common/PostCard.tsx
+++ b/src/components/common/PostCard.tsx
@@ -83,7 +83,7 @@ function PostCard({ post, forHome, forPost }: PostCardProps) {
             alt={`user thumbnail of ${post.user.username}`}
           />
           <span>
-            by <b>{post.user.profile.display_name}</b>
+            by <b>{post.user?.profile?.display_name ?? post.user.username}</b>
           </span>
         </VLink>
         <div className="likes">