PURPOSE: To ensure the compensation over a wide temperature range and thus to realize the improvement for the temperature characteristics, connecting several capacitors of different temperature coefficients to the MOS inverter functioning as the oscillating active element and via the gate circuit which is controlled according to the temperature.

CONSTITUTION: Bias resistance 2 is connected between the input and the output of amplifier 1, and furthermore the serial circuit of crystal oscillator 3 and trimmer capacitor 4 is connected in parallel to amplifier 1. On the other hand, the capacitor 6 is connected between the output side and the ground, and then capacitors 5 and 5' are connected to the input side via gate circuits 7 and 7'. The different temperature coefficients are secured between capacitors 5 and 5', and output signal Vout of Schmitt circuit 10 is applied to circuit 7 via inverter 11 along with the direct connection to circuit 7' each. Then the serial circuit of resistance 8 and semifixed resistance 9 is connected to circuit 10, and the temperature coefficients are set for resistance 9 plus capacitors 5 and 5' each. Then circuits 7 and 7' are selected in accordance with the temperature detected by resistance 8. Thus the temperature characteristics of the oscillating circuit is compensated over a wide range.