PROBLEM TO BE SOLVED: To provide a temperature control circuit for a laser diode that can suppress a processing load to increase the response speed of temperature control.SOLUTION: A temperature control circuit for a laser diode has a temperature detector 14 for detecting the temperature of LD 10, a thermoelectric element 13 for controlling the temperature of LD 10 by absorbing/wasting heat according to a flowing current amount, a temperature control processor 15 for calculating the amount of current to flow through the thermoelectric element 13 on the basis of the temperature detected by the temperature detector 14, a current controller 16 for controlling the current to flow through the thermoelectric element 13 on the basis of the current amount calculated by the temperature control processor 15, and a sampling period controller 17 for shortening a sampling period as a temperature detection period of the temperature detector 14 for a certain time period when release of a light emission stop state of LD10 is
