Abstract: A temperature control circuit comprises a temperature detection circuit for detecting the temperature of an object and outputting a temperature detection voltage, a first reference voltage generation circuit for generating a first reference voltage that corresponds to the upper limit of a predetermined suitable temperature range, a second reference voltage generation circuit for generating a second reference voltage that corresponds to the lower limit of the suitable temperature range, a first temperature comparison circuit for comparing the temperature detection voltage with the first reference voltage, a second temperature comparison circuit for comparing the temperature detection voltage with the second reference voltage, a temperature control signal generation circuit for generating a temperature control signal for controlling ON/OFF of a power supply of a cooler based on outputs signals of the first and second temperature comparison circuit, and a temperature control circuit for setting ON/OFF the power