Abstract: A server load sharing system having a plurality of server load balancers and a relay device. Each balancer includes a module selecting, any one of a plurality of load sharing target servers specified in their group on the basis of the virtual IP address and each allocated a unique IP address, and a module rewriting a virtual IP address of the received forwarding target packet addressed to the virtual IP address into the unique IP address of the selected server, and rewriting a source IP address of the received packet addressed to the virtual IP address into an IP address capable of specifying the other of the first and second links.