diff --git a/f_install/j_create_admin.php b/f_install/j_create_admin.php
index 6d6d6d9c..1a08cd9f 100644
--- a/f_install/j_create_admin.php
+++ b/f_install/j_create_admin.php
@@ -25,7 +25,7 @@ if(strlen($password)!=128){
     ]);
 }
 
-if(!class_exists('sammo\RootDB')){
+if(!class_exists('\\sammo\\RootDB')){
     Json::die([
         'result'=>false,
         'reason'=>'DB 설정이 완료되지 않았습니다.'
diff --git a/f_install/j_install_status.php b/f_install/j_install_status.php
index 1a247007..54f7032a 100644
--- a/f_install/j_install_status.php
+++ b/f_install/j_install_status.php
@@ -16,7 +16,7 @@ function dbSQLFail($params){
     ]);
 }
 
-if(!class_exists('sammo\RootDB')){
+if(!class_exists('\\sammo\\RootDB')){
     Json::die([
         'step'=>'config'
     ]);
diff --git a/f_install/j_setup_db.php b/f_install/j_setup_db.php
index f0c5402c..bc9b1029 100644
--- a/f_install/j_setup_db.php
+++ b/f_install/j_setup_db.php
@@ -45,7 +45,7 @@ if(file_exists(ROOT.'/d_setting/RootDB.php') && is_dir(ROOT.'/d_setting/RootDB.p
     ]);
 }
 
-if(class_exists('sammo\RootDB')){
+if(class_exists('\\sammo\\RootDB')){
     Json::die([
         'result'=>false,
         'reason'=>'이미 RootDB.php 파일이 있습니다'
diff --git a/index.php b/index.php
index 4543c633..29f84a6a 100644
--- a/index.php
+++ b/index.php
@@ -3,7 +3,7 @@ namespace sammo;
 
 require('_common.php');
 
-if(!class_exists('sammo\RootDB')){
+if(!class_exists('\\sammo\\RootDB')){
     header ('Location:install.php');
     die();
 }
diff --git a/src/kakao/kakao.php b/src/kakao/kakao.php
index 7886fb99..79642535 100644
--- a/src/kakao/kakao.php
+++ b/src/kakao/kakao.php
@@ -1,7 +1,7 @@
 <?php
 namespace kakao;
 
-if (class_exists('sammo\KakaoKey') === false) {
+if (class_exists('\\sammo\\KakaoKey') === false) {
   class KakaoKey{
     const REST_KEY = '';
     const ADMIN_KEY = '';
diff --git a/src/sammo/AppConf.php b/src/sammo/AppConf.php
index 2cfb5cae..4893987f 100644
--- a/src/sammo/AppConf.php
+++ b/src/sammo/AppConf.php
@@ -27,7 +27,7 @@ class AppConf{
      * @return \MeekroDB 
      */
     public static function requireRootDB(){
-        if(!class_exists('sammo\RootDB')){
+        if(!class_exists('\\sammo\\RootDB')){
             trigger_error('RootDB.php가 설정되지 않았습니다.', E_USER_ERROR);
             die();
         }
@@ -40,7 +40,7 @@ class AppConf{
      * @return \MeekroDB 
      */
     public static function requireDB(){
-        if(!class_exists('sammo\DB')){
+        if(!class_exists('\\sammo\\DB')){
             trigger_error('DB.php가 설정되지 않았습니다.', E_USER_ERROR);
             die();
         }
diff --git a/test.php b/test.php
index 9d29b002..1571b2de 100644
--- a/test.php
+++ b/test.php
@@ -5,5 +5,5 @@ require('vendor/autoload.php');
 Json::die([
     'haha',
     RootDB::getServerBasepath(),
-    'RootDB'=>class_exists('sammo\\RootDB')
+    'RootDB'=>class_exists('\\sammo\\RootDB')
 ]);
\ No newline at end of file