diff --git a/dictation_client/src/pages/TopPage/index.tsx b/dictation_client/src/pages/TopPage/index.tsx
index 7602aef..db2f4ca 100644
--- a/dictation_client/src/pages/TopPage/index.tsx
+++ b/dictation_client/src/pages/TopPage/index.tsx
@@ -44,7 +44,15 @@ const TopPage: React.FC = (): JSX.Element => {
               <dt>Already have an account?</dt>
               <dd>
                 {/* eslint-disable */}
-                <a onClick={() => instance.loginRedirect(loginRequest)}>
+                <a
+                  onClick={() => {
+                    // AADB2Cのサインイン画面に言語選択情報を渡す追加のクエリパラメータを設定
+                    loginRequest.extraQueryParameters = {
+                      ui_locales: i18n.language,
+                    };
+                    instance.loginRedirect(loginRequest);
+                  }}
+                >
                   Sign in
                   <img src="../../assets/images/arrow_forward.svg" alt="" />
                 </a>