Patent ID: 8498317

Claim:
A temperature controller for a gas laser comprising: a laser apparatus having a discharge portion to be filled up with a gaseous amplifiable agent, the discharge portion having a discharge electrode connected to a power supply unit; a pipe connected to the discharge portion; a heat exchanger cooling or heating cooling water to be supplied to the discharge portion via the pipe; an energy and/or power detector detecting energy and/or power of a laser light amplified by passing through the discharge portion; a temperature control portion temperature-controlling the discharge portion using the cooling water based on a detection result by the energy and/or power detector; and a thermal regulator controlling cooling or heating by the heat exchanger, the temperature control portion controlling a temperature of the discharge portion by adjusting a temperature of the cooling water to be supplied to the discharge portion by controlling the thermal regulator based on energy and/or power detected by the energy and/or power detector.