To provide an antenna switching diversity system capable of holding excellent communication quality by selecting an antenna whose receiving condition at a side of a mobile station is supposed to be the best and performing transmission.

A base station 10 is provided with plural antennas 11-1 to 11-4, receivers 13-1 to 13-4, switching units 12-1 to 12-4, a transmitter 19 and a prediction circuit 16 to connect the respective antennas 11-1 to 11-4 with the receivers 13-1 to 13-4 while transmission is performed by a mobile station 30, to detect a receiving level of receiving burst to be received by respective antennas and an error condition of received data from outputs of the receivers and to predict from which antenna among the plural antennas the transmission is started to make the receiving condition of the mobile station 30 best in a transmission timing of the base station 10 and the antenna whose receiving condition at the mobile station 30 is predicted to be the best by the prediction circuit 16 is connected with the transmitter by the switching unit when the transmission is performed by the base station 10 and the transmission is performed.