An amplifier includes: a package which includes a pair of edge portions; an input terminal which is provided in the edge portion; output terminals which are provided in the edge portion; a first-stage FET chip which includes an input port directly connected to the input terminal by a bonding wire; a first-stage terminal which is provided in the edge portion and is directly connected to an output port of the first-stage FET chip by a bonding wire; a second-stage terminal which is provided in the edge portion; a second-stage FET chip which includes an output port directly connected to output terminals and by a bonding wire; and an impedance matching capacitor element of which one electrode is connected to the second-stage terminal and the input port of the second-stage FET chip.