To suppress mutual interference during receiving operation and to accurately select high receiving sensitivity by switching an antenna based upon electric field intensity.

A receiving circuit 121 detects the electric field intensity of a received signal and applies the detected result to a CPU 122 to judge an antenna to be used for reception. Namely, when the electric field intensity of a signal received by a 1st vertical 1/4 wavelength whip antenna 101 is higher than that of a signal received by a 2nd horizontal half wavelength dipole antenna 102, the CPU 122 reversely bias-controls the diode 115 and forwardly controls the diode 116 to short-circuit the connecting point 131 and open the connecting point between the antenna 102 and two parallel 1/4 wavelength feeder 108. Also, when the electric field intensity of antenna 102 is higher, the CPU 122 controls the forward and reverse biases of diodes 15, 16, opens a node 113 and closes a node between the antenna 102 and the feeder 108. Further, impedance matching among the antennas 101, 102 and the circuit 121 is executed by 1st and 2nd matching means 109, 108.