A temperature compensating circuit is provided in a radio unit, an ambient temperature is detected by a temperature sensor of the temperature compensating circuit, the detected temperature value is supplied to a correction address storage section as an address after it is converted to a digital value, and thus a correction address corresponding to a correct temperature value obtained by correcting the detected temperature value is read out. Then, the correction address is supplied to a frequency correction data storage section to read out frequency correction data corresponding to the corrected temperature value, and the frequency correction data is converted to an analog control voltage by a D/A converter and then supplied to a variable capacitance element of a reference oscillator, thereby making it possible to correct the reference oscillation frequency according to the temperature.