PURPOSE: To reduce outside attached parts and make easy to form into an IC by applying sampling clock pulses to an integrating circuit with a temperature depending property to detect a temperature from the shift of pulses caused by the temperature and temperature-compensate an oscillating frequency.

CONSTITUTION: Sampling clock pulses are applied to a time constant circuit 8a which consists of a linearizing resistor R, a thermistor Th and a capacitor C and whose time constant varies with temperature. And the output of this circuit 8a is applied to one of the inputs of an exclusive OR gate 8d via an inverter 8b and an inverter 8c which are inverted when their integrated voltages become above a certain value. To the other input of the exclusive OR gate 8d, sampling pulses which passed a time delay circuit 8e which causes a certain amount of time delay are applied. Taking the AND 8f of the output of the exclusive OR gate 8d and clock pulses CK of a high frequency and executing computation, an interrupt pulse is applied to a frequency dividing circuit.