To provide a compact and inexpensive clock generator capable of outputting a highly accurate clock signal over a wide temperature range.

A clock generator includes a reference clock generating part 11 which generates a reference clock signal, a first oscillator 12 which generates a first clock signal, a first accuracy guaranteeing part 13 which generates a second clock signal in which the first clock signal is corrected to have the same frequency and the same phase as the reference clock signal, a temperature detection part 15, a second oscillator 17 which generates a third clock signal, a second accuracy guaranteeing part 18 which generates a fourth clock signal in which the third clock signal is corrected to have the same frequency and the same phase as the reference clock signal, and a clock switching part 20 which outputs the second clock signal when a temperature is within a guaranteed temperature range of the first oscillator 12 and outputs the fourth clock signal when the temperature is not within the guaranteed temperature range of the first oscillator 12.