To provide a method and device for appropriately registering communication terminal to satellite communication system.

A mobile terminal 2 for use in a satellite communication system capable of varying transmission area is provided with a receiver 8 which receives a call to one of spot beam transmitting channels and finishes the reception of the call substantially, a means which determines substantially whether or not one spot beam transmitting channel can receive to the mobile terminal 2 and transmits a registration message to a global beam receiving channel when one spot beam transmitting channel cannot receive, and a means which receives a spot beam channel distribution signal to a global beam transmitting channel and adjusts the receiver 8 so as to receive the spot beam transmitting channel selected according to the further spot beam channel distribution signal.