A mobile station apparatus controls the transmission method of uplink signals to efficiently transmit uplink control information, while avoiding increase of overhead of the control information. The mobile station apparatus has a reception processing unit 401 which performs detection processing of a physical downlink control channel in a plurality of cells, an uplink control information generating unit 4051 which generates a reception confirmation response to data of one or more physical downlink shared channels for which assignment of a resource is indicated by downlink control information included in one or more physical downlink control channels detected in a same subframe by the reception processing unit 401, a control unit 405 which controls application of transmission diversity to a physical uplink control channel according to a situation of a cell in which the physical downlink shared channel has been detected by the reception processing unit 401, and a transmission processing unit 407 which transmits the reception confirmation response generated in the uplink control information generating unit according to a control result of the control unit 405, using the physical uplink control channel.