An oscillator includes: an outer package having an accommodation space; an inner package accommodated in the accommodation space and fixed to the outer package via a heat insulating member; a vibration element accommodated in the inner package; a heat generation element accommodated in the accommodation space and fixed to the inner package; an oscillation circuit configured to oscillate the vibration element; a control circuit disposed outside the accommodation space and configured to control the heat generation element; and a conductive wire electrically coupling the outer package and the inner package.