According to one embodiment, a radio device comprises a differential antenna that has a pair of differential power supply terminals, a transmitter that transmits a first signal via the differential antenna, a receiver that has a pair of differential input terminals and receives a second signal via the differential antenna, a first control unit, and a second control unit. The first control unit causes a signal conduction state between the differential antenna and the receiver when the receiver receives the second signal. The second control unit switches from a signal conduction state to a signal block state between one of the differential input terminals and one of the differential power supply terminals based on a reception state when the receiver receives the second signal.