An oscillator includes: a resonator; a heat generation circuit configured to heat the resonator; a temperature sensor positioned closer to the heat generation circuit than the resonator is and configured to output a temperature detection signal; a temperature control circuit configured to output a temperature control signal for controlling a temperature of the heat generation circuit based on the temperature detection signal; an oscillation clock signal output circuit configured to oscillate the resonator and output an oscillation clock signal; and a correction circuit configured to correct a frequency variation of the oscillation clock signal, in which the correction circuit is configured to compensate for a transient frequency variation of the oscillation clock signal based on a time change amount of the temperature detection signal or a time change amount of the temperature control signal.