A mobile communication system transfers a packet to a mobile communication terminal forming an adhoc network, through a core network, based on address information of the mobile communication terminal. The address information of the mobile communication terminal includes common information which is changed when a connection point between the adhoc network and the core network is changed, and individual information which is maintained unchanged even when the connection point between the adhoc network and the core network is changed. The packet is configured to be transferred based on the individual information in a communication within the adhoc network.