PURPOSE: To receive the road side traffic information service with an easy operation without adding a presetting button by switching to a frequency for a road side traffic information service by one press-down of a service request push button and switching to a preliminary frequency by two press-downs.

CONSTITUTION: A condition counter provided in a control circuit CONT, when the service request push button in a key matrix KMX is first pushed down, become from '0' to '1' and when it is continuously pushed down, becomes from '1' to '2'. When a prescribed time passes after the counted value becomes '2', the counter returns to '0'. When the counted value is '1', it is decided whether or not the frequency is f1=1620KHz, when f1 is not obtained, the frequency dividing ratio corresponding to the frequency during the present reception is saved in a register, the frequency-dividing ratio corresponding to the f1 is read from a memory and outputted from the CONT to a phase lock loop PLL. Next, when it is decided when the counted value is 2, it is decided whether or not the frequency during the present reception is f2=1629KHz. When f2 is not obtained, the frequency-dividing ratio corresponding to the f2 is read from a memory and outputted to the PLL.