diff --git a/modules/utils.js b/modules/base.js
similarity index 96%
rename from modules/utils.js
rename to modules/base.js
index 59819086..b6aa64f5 100644
--- a/modules/utils.js
+++ b/modules/base.js
@@ -33,7 +33,7 @@
  *
  * ***** END LICENSE BLOCK ******/
  
-const EXPORTED_SYMBOLS = ['TreeStyleTabUtils']; 
+const EXPORTED_SYMBOLS = ['TreeStyleTabBase']; 
 
 const Cc = Components.classes;
 const Ci = Components.interfaces;
@@ -81,7 +81,7 @@ XPCOMUtils.defineLazyGetter(this, 'confirmWithPopup', function() {
 	return ns.confirmWithPopup;
 });
  
-var TreeStyleTabUtils = { 
+var TreeStyleTabBase = { 
 	__proto__ : window['piro.sakura.ne.jp'].prefs,
 	tabsHash : null,
 	inWindowDestoructionProcess : false,
@@ -2732,16 +2732,16 @@ var TreeStyleTabUtils = {
  
 	applyOnlyForActiveWindow : false, 
 	setPrefForActiveWindow : function(aTask) {
-		TreeStyleTabUtils.applyOnlyForActiveWindow = true;
+		TreeStyleTabBase.applyOnlyForActiveWindow = true;
 		try {
 			aTask.call(this);
 		}
 		finally {
-			TreeStyleTabUtils.applyOnlyForActiveWindow = false;
+			TreeStyleTabBase.applyOnlyForActiveWindow = false;
 		}
 	}
   
 }; 
  
-TreeStyleTabUtils.init(); 
+TreeStyleTabBase.init(); 
   
diff --git a/modules/fullTooltip.js b/modules/fullTooltip.js
index 530f1939..8b58c717 100644
--- a/modules/fullTooltip.js
+++ b/modules/fullTooltip.js
@@ -38,7 +38,7 @@ const EXPORTED_SYMBOLS = ['FullTooltipManager'];
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 
-Components.utils.import('resource://treestyletab-modules/utils.js');
+Components.utils.import('resource://treestyletab-modules/base.js');
 Components.utils.import('resource://treestyletab-modules/pseudoTreeBuilder.js');
 
 function FullTooltipManager(aOwner)
@@ -46,7 +46,7 @@ function FullTooltipManager(aOwner)
 	this.init(aOwner);
 }
 FullTooltipManager.prototype = {
-	__proto__ : TreeStyleTabUtils,
+	__proto__ : TreeStyleTabBase,
 
 	kTOOLTIP_MODE_DEFAULT   : 0,
 	kTOOLTIP_MODE_COLLAPSED : 1,
diff --git a/modules/groupTab.js b/modules/groupTab.js
index 3d344c51..20a6d04a 100644
--- a/modules/groupTab.js
+++ b/modules/groupTab.js
@@ -38,7 +38,7 @@ const EXPORTED_SYMBOLS = ['GroupTab'];
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 
-Components.utils.import('resource://treestyletab-modules/utils.js');
+Components.utils.import('resource://treestyletab-modules/base.js');
 Components.utils.import('resource://treestyletab-modules/pseudoTreeBuilder.js');
 
 function GroupTab(aWindow)
@@ -48,7 +48,7 @@ function GroupTab(aWindow)
 }
 
 GroupTab.prototype = {
-	__proto__ : TreeStyleTabUtils,
+	__proto__ : TreeStyleTabBase,
 
 	initialized : false,
 	shouldUpdate : false,
diff --git a/modules/pseudoTreeBuilder.js b/modules/pseudoTreeBuilder.js
index 5d63866f..cbce37c6 100644
--- a/modules/pseudoTreeBuilder.js
+++ b/modules/pseudoTreeBuilder.js
@@ -40,7 +40,7 @@ const Ci = Components.interfaces;
 
 Components.utils.import('resource://gre/modules/XPCOMUtils.jsm');
 
-XPCOMUtils.defineLazyModuleGetter(this, 'TreeStyleTabUtils', 'resource://treestyletab-modules/utils.js');
+XPCOMUtils.defineLazyModuleGetter(this, 'TreeStyleTabBase', 'resource://treestyletab-modules/base.js');
 
 var PseudoTreeBuilder = {
 
@@ -105,7 +105,7 @@ var PseudoTreeBuilder = {
 		if (w.isBlankPageURL ? !w.isBlankPageURL(uri) : (uri != 'about:blank')) tooltip += '\n' + uri;
 		label.setAttribute('tooltiptext', tooltip);
 		label.setAttribute('class', 'text-link '+this.kTREEITEM);
-		label.setAttribute('tab-id', TreeStyleTabUtils.getTabValue(aTab, TreeStyleTabUtils.kID));
+		label.setAttribute('tab-id', TreeStyleTabBase.getTabValue(aTab, TreeStyleTabBase.kID));
 
 		var children = this.createTabChildren(aTab);
 		if (children) {
@@ -123,7 +123,7 @@ var PseudoTreeBuilder = {
 	{
 		var doc = aTab.ownerDocument;
 
-		var children = TreeStyleTabUtils.getChildTabs(aTab);
+		var children = TreeStyleTabBase.getChildTabs(aTab);
 		if (!children.length)
 			return null;
 
diff --git a/modules/themeManager.js b/modules/themeManager.js
index 62c6bb16..09a28481 100644
--- a/modules/themeManager.js
+++ b/modules/themeManager.js
@@ -37,7 +37,7 @@ const EXPORTED_SYMBOLS = ['TreeStyleTabThemeManager'];
 
 const BASE = 'chrome://treestyletab/skin/';
 
-Components.utils.import('resource://treestyletab-modules/utils.js');
+Components.utils.import('resource://treestyletab-modules/base.js');
 
 function TreeStyleTabThemeManager(aWindow)
 {
diff --git a/modules/window.js b/modules/window.js
index 86305118..30099b0d 100644
--- a/modules/window.js
+++ b/modules/window.js
@@ -42,7 +42,7 @@ Components.utils.import('resource://gre/modules/XPCOMUtils.jsm');
 
 XPCOMUtils.defineLazyModuleGetter(this, "Services", "resource://gre/modules/Services.jsm");
 
-Components.utils.import('resource://treestyletab-modules/utils.js');
+Components.utils.import('resource://treestyletab-modules/base.js');
 XPCOMUtils.defineLazyGetter(this, 'TreeStyleTabBrowser', function() {
 	var ns = {};
 	Components.utils.import('resource://treestyletab-modules/browser.js', ns);
@@ -71,8 +71,8 @@ function TreeStyleTabWindow(aWindow)
 
 TreeStyleTabWindow.prototype = {
 	
-	utils : TreeStyleTabUtils, 
-	__proto__ : TreeStyleTabUtils,
+	utils : TreeStyleTabBase, 
+	__proto__ : TreeStyleTabBase,
  
 	window : null, 
 	document : null,