PURPOSE: To perform temperature compensation over a wide range of temperatures, by constituting a control circuit which produces an output indicating a secondary temperature characteristics opposite to those of a crystal oscillator circuit by using a thermistor and posistor.

CONSTITUTION: At a temperature lower than T, the resistance value of a thermistor 6 is higher than that of a posistor 7 and the output voltage of an R/V converter circuit 8 becomes higher than that of another R/V converter circuit 9. The output voltage of the circuit 8 is selected at a selection circuit 11 by the output of a comparator circuit 10. The voltage is converted into a frequency by means of a V/F converter circuit 12 and a correcting signal corresponding to the frequency is generated from a correction controlling circuit 13. At a correction circuit 4, temperature compensation is performed by adding or extracting the correcting signal to or from a pulse from a frequency dividing circuit 3. At a temperature higher than the T, the voltage of the R/V converter circuit 9 is selected since the output voltage of the circuit 9 becomes higher than that of the over R/V converter circuit 8, and the temperature compensation is performed in accordance with the voltage of the circuit 9.