PURPOSE: To prevent tuning-out by automatically compensating a local oscillation frequency by making a temperature sensing element detect a temperature where the cancellation of a temperature coefficient is disabled.

CONSTITUTION: To the base of transistor in mixing and local-oscillation circuit 13 with a temperature compensating function, a bias circuit composed of resistance R1 and thermistor 7 is connected. Transistor 8 is cut off nearly at the normal temperature. As a result, a voltage applied to a varactor diode is equal to Vcc. At a temperature where temperature coefficients of the oscillation circuit, coil and capacitor can not be canceled, the resistance value of thermistor 7 falls and transistor 8 starts conducting. As a result, the voltage applied to varactor diode 9 drops and electrostatic capacity increases, thereby correcting the oscillation frequency. At this time, the increase rate of the electrostatic capacity is variable with resistance R2.