A mobile terminal in a mobile communication system in which a server performs routing control based on registration information sent from the plurality of mobile terminals, including; an exchanging unit configured to exchange, with another mobile terminal, link information showing a link set in the another mobile terminal, and operational information showing whether the another mobile terminal is operating as a registering terminal which sends the registration information to the server or the another mobile terminal is operating as a non-registering terminal which does not send the registration information to the server; and a judgment unit configured to make a judgment on whether the mobile terminal should operate as the registering terminal or the mobile terminal should operate as the non-registering terminal, based on the link information and the operational information which are received from the another mobile terminal.