A radio base station control device instructs the radio base station device of a handover destination to establish a radio link with a mobile station terminal and requests the radio base station device of a handover source to report transmission power information concerning the down radio link to the mobile station terminal. In response to the request from the radio base station control device, the radio base station device of the handover source reports the transmission power information concerning the down radio link to the radio base station control device. The radio base station control device transfers the transmission power information from the radio base station device of the handover source to radio base station device of the handover destination. The radio base station device of the handover destination controls the transmission power of down link to the mobile station terminal by using the transferred transmission power information until synchronization of the up radio link is established.