A high-frequency switch module includes a switch IC, a phase adjustment circuit, and a filter circuit. The phase adjustment circuit, which includes an inductor and capacitors, includes a π-type circuit in which the inductor is connected in series between an individual terminal and the filter circuit. The filter circuit is an LC parallel resonant circuit including a filter inductor and a filter capacitor. A distortion second harmonic signal from the individual terminal of the switch IC is reflected by the filter circuit through the phase adjustment circuit and returns to the switch IC through the phase adjustment circuit. This distortion second harmonic signal, whose phase is adjusted by the phase adjustment circuit, is cancelled out by a distortion second harmonic signal output to a common terminal of the switch IC.