diff --git a/backend/routes/auth/signup.js b/backend/routes/auth/signup.js
index 0196a79..20acbf6 100644
--- a/backend/routes/auth/signup.js
+++ b/backend/routes/auth/signup.js
@@ -3,7 +3,8 @@ const router = express.Router();
 const defineUser = require("../../models/users");
 const { DataTypes } = require("sequelize");
 const roles = require("./roles");
-const bcrypt = require('bcrypt');
+const bcrypt = require("bcrypt");
+const jwt = require("jsonwebtoken");
 
 module.exports = function (sequelize) {
   const User = defineUser(sequelize, DataTypes);
@@ -19,14 +20,20 @@ module.exports = function (sequelize) {
           ? roles.findIndex((entry) => entry.uid === "user")
           : roles.findIndex((entry) => entry.uid === "admin");
 
-      await User.create({
+      const user = await User.create({
         email,
         password: hashedPassword,
         username: username,
         role: initialRole,
         avatarPath: null,
       });
-      res.status(201).json({ message: "User registered successfully" });
+
+      const accessToken = jwt.sign({ userId: user.id }, "your-secret-key", {
+        expiresIn: "1h",
+      });
+
+      user.password = undefined;;
+      res.status(200).json({ access_token: accessToken, user });
     } catch (error) {
       console.error(error);
       res.status(500).send("Sign up failed");
diff --git a/frontend/messages/ja.json b/frontend/messages/ja.json
index 1c10f55..4b41664 100644
--- a/frontend/messages/ja.json
+++ b/frontend/messages/ja.json
@@ -39,8 +39,8 @@
     "password_not_match": "パスワードが一致しません",
     "email_already_exist": "登録済みのメールアドレスです",
     "email_not_exist": "メールアドレスが見つかりません",
-    "signup_error": "新規登録できません",
-    "signin_error": "サインインできません"
+    "signup_error": "新規登録に失敗しました",
+    "signin_error": "サインインに失敗しました"
   },
   "Projects": {
     "projectList": "プロジェクト一覧",
diff --git a/frontend/src/app/[locale]/auth/authControl.ts b/frontend/src/app/[locale]/auth/authControl.ts
index ba8db42..f7470c0 100644
--- a/frontend/src/app/[locale]/auth/authControl.ts
+++ b/frontend/src/app/[locale]/auth/authControl.ts
@@ -18,10 +18,10 @@ async function signUp(newUser: UserType) {
     if (!response.ok) {
       throw new Error(`HTTP error! Status: ${response.status}`);
     }
-    const data = await response.json();
-    return data;
+    const accessToken = await response.json();
+    storeToken(accessToken);
   } catch (error: any) {
-    console.error("Error creating sign up:", error);
+    console.error("Error sign up:", error);
     throw error;
   }
 }
@@ -42,12 +42,20 @@ async function signIn(signInUser: UserType) {
     if (!response.ok) {
       throw new Error(`HTTP error! Status: ${response.status}`);
     }
-    const data = await response.json();
-    return data;
+    const accessToken = await response.json();
+    storeToken(accessToken);
   } catch (error: any) {
     console.error("Error sign in:", error);
     throw error;
   }
 }
 
-export { signUp, signIn };
+function storeToken(accessToken: Object) {
+  localStorage.setItem("testplat-auth-token", JSON.stringify(accessToken));
+}
+
+function signOut() {
+  localStorage.removeItem("testplat-auth-token");
+}
+
+export { signUp, signIn, signOut };
diff --git a/frontend/src/app/[locale]/auth/authPage.tsx b/frontend/src/app/[locale]/auth/authPage.tsx
index 1488f3c..3f7a682 100644
--- a/frontend/src/app/[locale]/auth/authPage.tsx
+++ b/frontend/src/app/[locale]/auth/authPage.tsx
@@ -58,13 +58,19 @@ export default function AuthPage({ isSignup, messages, locale }: Props) {
 
   const submit = async () => {
     if (isSignup) {
-      const signUpRet = await signUp(user);
-      console.log(signUpRet);
-      // if success, move to signin page
+      try {
+        await signUp(user);
+        // Move to signin page
+      } catch {
+        setErrorMessage(messages.signupError);
+      }
     } else {
-      const signInRet = await signIn(user);
-      console.log(signInRet);
-      // if success, move to account page
+      try {
+        signIn(user);
+        // Move to signin page
+      } catch {
+        setErrorMessage(messages.signinError);
+      }
     }
   };