pa 63 is an amplifier that is used only when the input power is high operates with a power supply voltage supplied from the power supply 52 amplifies the power of a transmission signal inputted from the distributor 61 and outputs the amplified signal to the compositor 66 via the output matching unit 65 the output matching unit 64 adjusts the output side impedance of the ca 62 the output matching unit 65 adjusts the output side impedance of the pa 63 the compositor 66 combines a signal inputted from the ca 62 via the output matching unit 64 with a signal inputted from the pa 63 via the output matching unit 65 and outputs the obtained composite signal as an output signal from an output terminal the power supply 52 is a power supply that supplies a power supply voltage to the amplification unit 51 the power supply 52 is coupled to the gate terminal of the ca 62 via a gate bias line 52 a and applies a predetermined gate voltage to the ca 62 using the gate bias line 52 a in addition the power supply 52 is coupled to the gate terminal of the pa 63 via a gate bias line 52 b and applies a predetermined gate voltage to the pa 63 using the gate bias line 52 b also the power supply 52 is coupled to the drain terminal of the ca 62 via a drain bias line 52 c.