Abstract: For supply to first and second feedforward distortion compensating circuits 33(1), 33(2) connected in parallel, a two-divider 31 divides into signals of a common phase and a common amplitude an input or composite radio frequency signal supplied to an input terminal 11. The composite radio frequency signal collectively has a plurality of radio frequency signals of different frequencies. A two-combiner 35 combines component outputs of the feedforward circuits in inphase as an amplified output signal which is supplied to an output terminal 13. In general, N feedforward circuits (N being an integer not less than two) are connected in parallel and are supplied with the input radio frequency signal through an N-divider. Component outputs of the feedforward circuits are combined in inphase as the output signal by an N-combiner. Alternatively, the input radio frequency signal is divided into signals of a predetermined phase difference and of a common amplitude by the N-divider.