A power amplifier includes: a semiconductor substrate; a preceding-stage amplifying device on the semiconductor substrate, amplifying an input signal; a following-stage amplifying device on the semiconductor substrate, amplifying an output signal of the preceding-stage amplifying device; and an inter-stage matching circuit connecting the preceding-stage amplifying device to the following-stage amplifying device. The preceding-stage amplifying device has a first field effect transistor; the following-stage amplifying device has a heterojunction bipolar transistor; and the inter-stage matching circuit has a capacitance galvanically separating the output terminal of the preceding-stage amplifying device from the input terminal of the following-stage amplifying device.