Configuration of a connection between an even-harmonic mixer and a filter is simplified, thereby enabling size reduction. An even-harmonic mixer (21) and a high-frequency bandpass filter (23) are connected to each other via a transmission line (22), thereby forming a filter-integrated even-harmonic mixer. The length of the transmission line (22) is set so that impedance on the transmission line side as viewed from a connection point (24) between the even-harmonic mixer (21) and the transmission line (22) is approximately 0 for a frequency fLO of a local oscillation signal. This allows elimination of an open stub which is used in a conventional even-harmonic mixer and of which the line length to provide equivalent grounding for the frequency fLO is about 1 mm. Thus, the connection portion between the even-harmonic mixer and the high-frequency bandpass filter is simplified and a compact circuit layout for the filter-integrated even-harmonic mixer is obtainable.