In-package temperature is controlled with higher accuracy. To this end, a temperature control circuit includes a temperature sensor arranged in a package and detecting temperature in the package, a heater current detection circuit detecting a driving amount of a heater, a target temperature generation circuit generating a target temperature from an intended temperature of a resonator and a detection value of the driving amount detected by the heater current detection circuit, a heater current driver controlling the heater so that the detection temperature detected by the temperature sensor coincides with the target temperature, and an Nth-order correction circuit receiving the detection value of the driving amount detected by the heater current detection circuit or a signal based on the target temperature and cancelling influence of a second or higher order fluctuation component generated in the heater current detection circuit on temperature of the resonator.