diff --git a/lib/core/storage.js b/lib/core/storage.js
index 3fbfdb2a9..b4e599803 100644
--- a/lib/core/storage.js
+++ b/lib/core/storage.js
@@ -227,7 +227,7 @@ export default class Storage {
     } else if (process.server && this.ctx.res) {
       // Send Set-Cookie header from server side
       const prevCookies = this.ctx.res.getHeader('Set-Cookie')
-      this.ctx.res.setHeader('Set-Cookie', [].concat(prevCookies, serializeCookie))
+      this.ctx.res.setHeader('Set-Cookie', [].concat(prevCookies, serializedCookie))
     }
 
     return value