In order to make full use of the performance of a Massive-MIMO-applied communication system, provided is a base station apparatus for controlling a transmission direction of a transmission beam for a synchronization signal used in cell search by beamforming using a plurality of antenna elements. The base station apparatus has a synchronization signal processing section (62) that generates the synchronization signal including information to identify the transmission beam for the synchronization signal and changes a beamforming weight for the synchronization signal at every given time interval; and a transmission section (64) that transmits the synchronization signal generated with the beamforming weight in downlink.