diff --git a/component/viewer/src/main/java/one/nem/lacerta/component/viewer/ViewerListFragment.java b/component/viewer/src/main/java/one/nem/lacerta/component/viewer/ViewerListFragment.java
index 790820b8..9cd49f37 100644
--- a/component/viewer/src/main/java/one/nem/lacerta/component/viewer/ViewerListFragment.java
+++ b/component/viewer/src/main/java/one/nem/lacerta/component/viewer/ViewerListFragment.java
@@ -187,7 +187,7 @@ public class ViewerListFragment extends Fragment {
                     return true;
                 } else if (item.getItemId() == R.id.action_delete) {
                     // TODO-rca: デザインをMaterial Design 3に合わせたカスタムダイアログにする
-                    AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
+                    MaterialAlertDialogBuilder builder = new MaterialAlertDialogBuilder(requireContext());
                     builder.setTitle("ファイルの削除");
                     builder.setMessage("ファイルを削除しますか？");
                     builder.setPositiveButton("削除", (dialog, which) -> {