diff --git a/frontend/src/pages/posts/PostHistoryPage.tsx b/frontend/src/pages/posts/PostHistoryPage.tsx
index 998fe6a..ab54ad2 100644
--- a/frontend/src/pages/posts/PostHistoryPage.tsx
+++ b/frontend/src/pages/posts/PostHistoryPage.tsx
@@ -71,7 +71,7 @@ export default (() => {
 			  ++rowsCnt
 		      }
 		    return (
-			<tr key={`${ change.timestamp }-${ change.post.id }-${ change.tag.id }`}
+			<tr key={`${ change.timestamp }-${ change.post.id }-${ change.tag?.id }`}
 			    className={cn ('even:bg-gray-100 dark:even:bg-gray-700',
 					   withPost && 'border-t')}>
 			  {withPost && (
@@ -94,7 +94,7 @@ export default (() => {
 			  <td className="p-2">
 			    {change.tag
 			     ? <TagLink tag={change.tag} withWiki={false} withCount={false}/>
-				 : '(マスタ削除済のタグ) '}
+			     : '(マスタ削除済のタグ) '}
 			    {`を${ change.changeType === 'add' ? '記載' : '消除' }`}
 			  </td>
 			  <td className="p-2">