To stabilize the oscillation frequency of an oscillation circuit which is using a crystal vibrator, etc., in terms of temperature, etc.

A resistor R1 is connected in series to a crystal vibrator X and a resistor R2 is connected in parallel to the vibrator X respectively. At the same time, a capacitor C2 is connected in series to the vibrator X to properly suppress the exciting level of the vibrator X and also to turn the oscillation frequency characteristic into a smooth tertiary curve corresponding to the temperature of the signal that is amplified by a transistor Q11 and outputted from an emitter. Thus, the temperature compensation is facilitated. Meanwhile, the power voltage supplied to an oscillation circuit of a microwave band, etc., using a dielectric resonator is varied by a temperature compensation circuit according to the temperatures to stabilize the oscillation frequency in regard to the temperature. In regard to the humidity, the relative humidity is detected by a humidity detection circuit. Then the temperature compensation circuit generates the control voltage in response to the relative humidity and controls the oscillation circuit to stabilize the oscillation frequency.