A pager includes a power supply that supplies a plurality of power sources of various voltages, a switch that selects a power source supplied by the power supply and supplies the power source to a frequency converter, and a controller that shifts the selection of the switch into another power source of higher voltage when extraction of an ID from a signal demodulated by a demodulator is impossible. The controller instructs the switch to select a power source of the lowest voltage in the initial state and after a predetermined time from the switching into the higher voltage power source. Signal distortion in the frequency converter, a factor causing intermodulation, is prevented by switching the power source voltage of the frequency converter. Deterioration of the possibility of reception due to intermodulation in the frequency converter is thereby prevented. The switch is returned to its initial state after a predetermined time and power consumption of the pager is reduced. The possibility of reception is improved even more if an attenuator is provided in front of an amplifier.