A high-frequency switch operating in a millimeter wave band that includes a signal path having a λ/4 transmission path, for part of two or more branch signal paths that branch from an input connection path via a branch point; an FET, which is shunt-connected between a grounding end and the branch signal paths that are positioned between the λ/4 transmission path and a terminal end, as viewed from the branch point, and used to connect or disconnect the branch signal paths and the grounding end; an output matching circuit, which is positioned on the branch signal paths that are positioned between a terminal end and a connection point for the FET as viewed from the branch point, and includes a shunt-connected stub; and a matching FET, which is connected between the stub and the grounding end and used to connect or disconnect the stub and the grounding end in accordance with the FET's connection/disconnection.