The clock signal output device has a crystal oscillator for generating a reference clock signal and generating and outputting an output clock signal having a prescribed frequency on the basis of the reference clock signal. The device also has an atomic oscillator for generating a clock signal having higher precision than a crystal oscillator, an intermittent time management unit for intermittently driving the atomic oscillator, and a correction unit for receiving correction data for correcting the offset amount of the output clock signal on the basis of a clock signal each time the atomic oscillator is driven, and correcting the output clock signal on the basis of the correction data.