The radio base station apparatus comprises: a plurality of antenna elements for transmitting and receiving radio signals; a detection unit for detecting information about an uplink dedicated channel corresponding to a first user equipment from signals received via the plurality of antenna elements; a directivity control unit for determining directivity of transmission power based on the information detected by the detection unit when signals are transmitted to the first user equipment via the downlink shared channel; and a transmission unit for transmitting signals with the directivity determined by the directivity control unit.