In a load balancer preserving a function of server consistency maintenance during communications even if a terminal is a mobile terminal, identifying information specific to a mobile IP terminal is extracted from an arrival packet, and a destination server to be connected is determined based on the identifying information. Also, a home agent or a terminal is requested to notify a change of the care-of address when the care-of address of the terminal has changed, and a destination server to be connected is determined by regarding the notified care-of address as identifying information.