There is provided a radio device including an antenna, a first impedance converting circuit, a second impedance converting circuit and a differential output unit. The antenna has a first terminal and a second terminal to receive a signal. The first impedance converting circuit and the second impedance converting circuit have a first impedance and a second impedance, respectively. The first impedance and the second impedance each are controllable. One end of the first impedance converting circuit and one end of the second impedance converting circuit are connected to the first terminal and the second terminal of the antenna, respectively. The differential output unit is connected to the other end of the first impedance converting circuit and the other end of the second impedance converting circuit through which the signal received by the antenna is input to the differential output unit, and transform the signal into a differential signal.