High-frequency amplifier

A high-frequency amplifier includes: a driving amplifier that amplifies an input high-frequency signal; and a Doherty amplifier including a carrier amplifier and a peak amplifier, the Doherty amplifier further amplifying a signal output by the drive amplifier, the high-frequency amplifier having: a first multilayer substrate; a second multilayer substrate stacked so as to overlap the first multilayer substrate; and a base member on which the first multi-layer substrate and the second multi-layer substrate are mounted, the drive amplifier being mounted on the second multi-layer substrate, the carrier amplifier and the peak amplifier being mounted on the first multi-layer substrate, and the peak amplifier being mounted on the second multi-layer substrate. The drive amplifier, the carrier amplifier, and the peak amplifier each have a front surface on which a predetermined circuit is formed, and a rear surface on the opposite side of the front surface, and the front surface of the drive amplifier faces the first