DISTANCE MEASURING DEVICE

A distance measuring device according to an embodiment includes a filter, a first switching circuit, an impedance adjustable circuit, a second switching circuit, a third switching circuit, and a fourth switching circuit. The filter restricts a signal for distance measurement transmitted from the transmission circuit and a signal for distance measurement received by an antenna within a desired frequency band. The impedance adjustable circuit is adjusted to have a higher impedance than an impedance of the antenna. The second switching circuit switches conduction and non-conduction between the impedance adjustable circuit and the transmission circuit. The third switching circuit switches conduction and non-conduction between the impedance adjustable circuit and the reception circuit. The fourth switching circuit switches conduction and non-conduction between the impedance adjustable circuit and the second switching circuit and between the impedance adjustable circuit and the third switching circuit.