A temperature-compensated oscillator includes a resonator element, an oscillating circuit, and a temperature compensation circuit, and a frequency deviation with respect to a frequency at a time point when power supply starts is within a range of ±8 ppb at a time point when 10 seconds elapse from when the power supply starts, within a range of ±10 ppb at a time point when 20 seconds elapse from when the power supply starts, and within a range of ±10 ppb at a time point when 30 seconds elapse from when the power supply starts.