Time required for location registration is reduced and concentration of location update signals caused when a group moves is prevented. Each mobile node and a mobile router sends a location update request to a local location manager near to the area in which it exists, so that time required for location registration can be reduced, and it is possible to prevent pressure on wireless resources and temporary increase in communication traffic within a mobile network, which may be caused by concentration of location update signals when a group moves as in the case of a train with a lot of passengers having mobile nodes. Thereby, even if location registration is not correctly performed by a mobile router, which sends a location update request on behalf of mobile nodes existing in the space of a moving body, due to the communication condition or a failure, it can be dealt with.