A low pass filter connected between an individual port of a switch device and a high-frequency switch module attenuates the second harmonic and the third harmonic of a transmission signal input to a first transmission signal input terminal. Further, the inductances/capacitances of inductors and capacitors defining the low pass filter are set such that the phase of a harmonic signal generated by a power amplifier is different by 180° from the phase of a harmonic signal produced as a result of the low pass filter shifting the phase of a harmonic signal generated due to distortion in a switch device, in an end portion on the first transmission signal input terminal side.