To make a device, for example, MN or HA owns a list where the HA to which location registration should be executed for a consideration address(CoA) is shown, and to dynamically assign the HA by referring to the list at the time of executing the location registration.

This mobile IP communication system is provided with a list managing server 14 having a list managing means which manages a list where a network domain is made to correspond to the location information of a home agent(HA) and a list sending means which sends at least a portion of the list and a communication terminal (MN) 22 having a list receiving means which receives the list from the list managing server 14, an HA selecting means which compares its own consideration address with a network domain in the list, and acquires the location information of the corresponding HA and a location registering means which executes the location registration to the HA based on the acquired location information of the HA.