A transmission power control method and a mobile station apparatus that can adequately control the transmission power of a mobile station apparatus having multiple transmitting antennas is disclosed. The uplink transmission power control for the mobile station apparatus measures the path loss of at least one transmitting antenna, sets a representative value path loss based on the measured path loss measurement value, determines a total transmission power of the mobile station apparatus based on the representative value path loss, and determines the transmission power of each transmitting antenna by distributing the total transmission power to the transmitting antennas.