diff --git a/lib/sso_login_box/login_tag.rb b/lib/sso_login_box/login_tag.rb
index 2140afe..9441de1 100644
--- a/lib/sso_login_box/login_tag.rb
+++ b/lib/sso_login_box/login_tag.rb
@@ -6,7 +6,7 @@ module SsoLoginBox::LoginTag
       }
     </style>
     <div class=\"pull-right\">
-        <a class=\"sso_login_button btn\" href=\"/oauth2_service/auth_page?referer_url=#{(URI.encode(OrbitHelper.request.original_url) rescue "")}\" style=\"border: 0.1em solid black;\">
+        <a class=\"sso_login_button btn\" href=\"/oauth2_service/auth_page?referer_url=#{(URI.encode(OrbitHelper.request.original_url.gsub('?','&')) rescue "")}\" style=\"border: 0.1em solid black;\">
           CCU SSO Login
         </a>
     </div>"