Web server is recently composed of a server cluster for keeping good quality of services in spite of suddenly rushed connections. LVS (Linux Virtual Server) is one of methods to build server cluster in Linux and it has its own load balancing mechanism [1]. The existing load balancing mechanism, however, reaches the limit often and fails to keep load in balance, in particularly electric commerce sites that use typically dynamic script files more than static HTML pages. In this paper, we suggest a new mechanism that overcome the limit and discuss how to define the load of each real server node in server cluster and determine the limit of the load. In the suggested mechanism, the weight table of a load balancer is updated according to the variation of the load and the distribution of service requests is controlled according to the table. The new mechanism shows better results to distribute the load evenly among the real servers than the existing mechanism, when many scripts are especially included.