Abstract: In order to detect microwaves from radar type speed measurement devices and microwaves leaking out of reverse detectors without being detected by such reverse detectors, a microwave detector is provided with a super-heterodyne type reception circuit for cyclically performing reception operations to receive target microwave frequencies of prescribed microwave bands, the reception circuit including a first local oscillator which can carry out a fixed oscillation at a prescribed frequency or a sweep of a prescribed frequency range established slightly outside the frequency range of the local oscillator of a reverse detector, and a plurality of second local oscillators having different oscillation frequencies, whereby the reception circuit is able to receive microwaves in the target bands and microwaves leaking out of the local oscillator of a reverse detector.