diff --git a/src/Users/Session.php b/src/Users/Session.php
index ef27365a..07ccea8a 100644
--- a/src/Users/Session.php
+++ b/src/Users/Session.php
@@ -1,6 +1,7 @@
 <?php
 namespace Misuzu\Users;
 
+use Carbon\Carbon;
 use Misuzu\Model;
 use Misuzu\Net\IP;