Master mobile station, slave mobile station, home location register, and mobile switching center

Concentrated use of wireless resources by location registrations carried out by slave mobile stations all together when a plurality of slave mobile stations present in a moving body provided with a master mobile station while bridging adjacent location registration areas is prevented. For this purpose, a mobile communications system 1 comprises: at least a broadcast information transmitting function unit ( 21 ) for notifying to the slave mobile stations ( 3 ) that the slave mobile stations are slaved to the master mobile station ( 2 ), a link maintaining function unit ( 31 ) for holding master-slave relationships, home location registers ( 5, 6 ) provided with expansion areas ( 52, 62 ) for holding the mobile station link information, and a mobile station link information forwarding function unit ( 41 ) for forwarding the address information of the master mobile station ( 2 ).