PURPOSE: To make temperature compensation for the circuit with a temperature compensating capacitor having the positive or negative temperature characteristics, by setting a top temperature of a quartz oscillator having the secondary temperature coefficient between the vicinity of an operating temperature range and outside of the operating range.

CONSTITUTION: A quartz oscillator Q has a secondary temperature coefficient and is cut out so that the frequency is maximum near the upper limit T1 of the operating temperature range T0∼T1. Since the oscillator Q has a positive temperature coefficient within the operating temperature range, the temperature compensation like a curve l2 can be made by using a temperature compensating capacitor having a positive temperature coefficient for either one or both of load capacitors C1 and C2. If the top temperature of the oscillator Q is set near the lower limit temperature T0, the temperature characteristics in the operating temperature range of the oscillator Q are negative. Thus, the temperature compensation like a curve l4 can be made by using a temperature compensating capacitor having a negative temperature coefficient.