A mobile station is for use in a code-division multiple-access communications system. The mobile station includes: a detection unit for receiving a signal transmitted from a base station and including a transmission-power control signal and for detecting an error in a downlink for the signal received; an extraction unit for extracting transmission-power control information from the signal received; and a mobile-station transmission-power control unit that receives a result of error detection performed by the detection unit and the transmission-power control information and controls the transmission power of a radio transmission unit of the mobile station. The mobile-station transmission-power control unit controls the radio transmission unit of the mobile station in accordance with the result of error detection, referring to the transmission-power control information, a history of an uplink transmission power for immediately preceding m frames and a history of the transmission-power control information for immediately preceding n frames.