A distance measuring device comprising: a transmission circuit configured to transmit a signal for distance measurement to another distance measuring device ; a reception circuit configured to receive the signal for distance measurement transmitted form the other distance measuring device ; a filter configured to restrict the signal for distance measurement transmitted from the transmission circuit and a signal for distance measurement received by an antenna within a desired frequency band; and a first switching circuit configured to switch a route between the transmission circuit and the antenna and a route between the reception circuit and the antenna , characterized in further comprising: an impedance circuit (R1) configured to have a higher impedance than an impedance of the antenna ; a second switching circuit ; a third switching circuit ; and a fourth switching circuit , wherein the second switching circuit is configured to switch conduction and non-conduction between the fourth switching circuit and the transmission circuit , the third switching circuit is configured to switch conduction and non-conduction between the fourth switching circuit and the reception circuit , and the fourth switching circuit is configured to switch conduction and non-conduction between the impedance circuit (R1) and both of the second switching circuit and the third switching circuit . a transmission circuit configured to transmit a signal for distance measurement to another distance measuring device ; a reception circuit configured to receive the signal for distance measurement transmitted form the other distance measuring device ; a filter configured to restrict the signal for distance measurement transmitted from the transmission circuit and a signal for distance measurement received by an antenna within a desired frequency band; and a first switching circuit configured to switch a route between the transmission circuit and the antenna and a route between the reception circuit and the antenna , characterized in further comprising: an impedance circuit (R1) configured to have a higher impedance than an impedance of the antenna ; a second switching circuit ; a third switching circuit ; and a fourth switching circuit , wherein the second switching circuit is configured to switch conduction and non-conduction between the fourth switching circuit and the transmission circuit , the third switching circuit is configured to switch conduction and non-conduction between the fourth switching circuit and the reception circuit , and the fourth switching circuit is configured to switch conduction and non-conduction between the impedance circuit (R1) and both of the second switching circuit and the third switching circuit . an impedance circuit (R1) configured to have a higher impedance than an impedance of the antenna ; a second switching circuit ; a third switching circuit ; and a fourth switching circuit , wherein the second switching circuit is configured to switch conduction and non-conduction between the fourth switching circuit and the transmission circuit , the third switching circuit is configured to switch conduction and non-conduction between the fourth switching circuit and the reception circuit , and the fourth switching circuit is configured to switch conduction and non-conduction between the impedance circuit (R1) and both of the second switching circuit and the third switching circuit . <EOS>