PROBLEM TO BE SOLVED: To provide a temperature control circuit capable of stabilizing an output frequency by stable temperature control, with the suppression of an influence of a power supply voltage variation.SOLUTION: The temperature control circuit includes: an operational amplifier 10 which outputs a difference between a reference voltage, which is output from a point between resistors R2, R3, and a voltage according to a temperature from a thermistor; and a PNP power transistor Tr1 which inputs to the base the output from the operational amplifier 10, to control the current of a heater resistor connected to the emitter. The temperature control circuit further includes a bridge resistor circuit 11 having one end connected to a power supply voltage Vcc, and resistors R11, R12 connected in series. A point between the resistors R11, R12 of the bridge resistor circuit 11 is connected through a resistor R13 to the point between the resistors R2, R3 which supplies the reference voltage. A voltage between the ba
