diff --git a/common.php b/common.php
index 5e528a392..c2a899795 100644
--- a/common.php
+++ b/common.php
@@ -382,7 +382,7 @@ if ($_SESSION['ss_mb_id']) { // 로그인중이라면
         $tmp_mb_id = substr(preg_replace("/[^a-zA-Z0-9_]*/", "", $tmp_mb_id), 0, 20);
         // 최고관리자는 자동로그인 금지
         if ($tmp_mb_id != $config['cf_admin']) {
-            $sql = " select mb_password, mb_intercept_date, mb_leave_date, mb_email_certify from {$g5['member_table']} where mb_id = '{$tmp_mb_id}' ";
+            $sql = " select mb_password, mb_intercept_date, mb_leave_date, mb_email_certify from {$g5['member_table']} where binary(mb_id) = '{$tmp_mb_id}' ";
             $row = sql_fetch($sql);
             $key = md5($_SERVER['SERVER_ADDR'] . $_SERVER['REMOTE_ADDR'] . $_SERVER['HTTP_USER_AGENT'] . $row['mb_password']);
             // 쿠키에 저장된 키와 같다면