PURPOSE: To give a monaural constitution to an earphone used as an antenna to simplify the circuit constitution by giving priority to reception by an external antenna at the time of connecting the external antenna and the earphone used as the antenna together.

CONSTITUTION: When the connection plug of the earphone is inserted to a connection jack 31 but that of the external antenna is not inserted into a connection jack 32, a rod antenna and a mobile contact 31a are disconnected from each other, and the reception signal of the earphone connected to the connection jack 31 is controlled by the jack 32 and is supplied to a tuner. At this time, the audio signal is emitted through the jack 31 by the earphone. When the connection plug or the earphone is inserted into the jack 31 and that of the external antenna is inserted into the jack 32, the audio signal from an audio amplification circuit is emitted through the plug connected to the jack 31 by the earphone. In this case, the monaural structure is given.