To not only miniaturize the shape of the whole of a radio device but also keep the signal purity of an oscillation circuit high to provide many reception channels by generating a selection voltage corresponding to user's designation contents and applying it to a varactor diode of a frequency selection part to adjust the tuning frequency of the frequency selection part.

When the user designates a reception channel, designation contents are fetched by a CPU circuit 2, and selection voltage data corresponding to designation contents is outputted from a voltage information table 7. It is converted into an analog signal by a D/A conversion part 8 and is applied to a varactor diode 3 of a frequency selection part 6. Then, the varactor diode 3 has a capacity corresponding to the frequency of a signal as the selection object, and the frequency selection part 6 selects the tuning frequency corresponding to the capacity of the varactor diode 3, the capacity of a capacitor 4, and the inductance of a coil 5, and the signal of the selection object frequency in the high frequency signal obtained by the antenna of the radio device is extracted.