An antenna selector selects one of the plurality of antennas according to an antenna selection signal. The antenna selector includes a voltage converter and an analog switch circuit. The voltage converter converts a power-supply voltage to a predetermined output voltage higher than the power-supply voltage. The analog switch circuit operates with the predetermined output voltage from the voltage converter or the power-supply voltage being applied thereto. A voltage converter controller controls the voltage converter to operate/halt according to a power level of the transmission signal generated by the transmitter. The predetermined output voltage is applied to the analog switch circuit when the voltage converter is operating and the power-supply voltage is applied to the analog switch circuit when the voltage converter is halted.