A surface acoustic wave duplexer includes a transmission-side surface acoustic wave filter and a receiving-side surface acoustic wave filter which are connected to an antenna terminal, and the transmission-side surface acoustic wave filter and the receiving-side surface acoustic wave filter are mounted on a package material. The surface acoustic wave duplexer further includes a high-frequency wave element which is connected to the transmission-side surface acoustic wave filter and the receiving-side surface acoustic wave filter, and at the same time, has two trap attenuation poles at the higher frequency side than at least the transmission-side pass band and the receiving-side pass band.