To obtain a small-sized power amplifier with an excellent frequency characteristic and low power consumption where a difference in a phase shift of a signal passing through a plurality of amplifier circuits is decreased for each frequency and the loss can be reduced.

A phase shift controller 8 controls a phase shift of phase shifters 3a, 3b so that a difference in the phase shifts of signals passing through amplifier circuits 7a, 7b is minimized for each frequency depending on the frequency in use on the basis of frequency information received from an input terminal 9 are the frequency information.