PURPOSE: To form the circuit inexpensively through the use of an oscillation section whose frequency change due to temperature is large and to obtain a constant frequency independently of the temperature.

CONSTITUTION: An output of a CR oscillation section 1 generating a signal of a reference frequency is frequency-divided by a frequency division section 2 to obtain a desired frequency. The temperature of the CR oscillation section 1 is detected by a temperature sensor 3 and an arithmetic operation section 4 calculates a frequency division ratio used to cancel an oscillation frequency change due to the temperature of the CR oscillation section 1 in response to the detection temperature. The frequency division section 2 frequency-divides an output of the CR oscillation section 1 by the calculated frequency division ratio.