Transmission power of a plurality of uplink carrier components used for radio communication by a mobile station device and a base station device is efficiently controlled. The mobile station device communicates by radio with the base station device using a plurality of component carriers. The mobile station device receives, from the base station device, downlink control information that includes information indicating radio resource assignment to a downlink shared channel disposed in any of downlink component carriers, and a TPC command to an uplink control channel in an uplink component carrier in which ACK/NACK to the downlink shared channel is transmitted.