diff --git a/app/views/admin/personal_plugin_fields/fields_setting.html.erb b/app/views/admin/personal_plugin_fields/fields_setting.html.erb
index 19127dd..7d9e350 100644
--- a/app/views/admin/personal_plugin_fields/fields_setting.html.erb
+++ b/app/views/admin/personal_plugin_fields/fields_setting.html.erb
@@ -106,8 +106,8 @@
     handle: ".brand",
     update: function(event, ui) {
       var new_index = ui.item.index();
-      var old_index = ui.item.attr("index");
-      var indices = [new_index,old_index].sort();
+      var old_index = parseInt(ui.item.attr("index"));
+      var indices = [new_index,old_index].sort(function(a,b){return a - b});
       for(var new_i=indices[0];new_i<=indices[1];new_i++){
         var td = ui.item.parent().find(">").eq(new_i);
         var old_i =td.attr("index");