Patent ID: 8675707

Claim:
A gas laser apparatus comprising: a laser power supply device having a DC power supply unit for converting input AC power into DC power and an RF power supply unit for converting the DC power, output from the DC power supply unit, into a radio-frequency voltage which is applied to produce an electric discharge for exciting a laser gas contained in a discharge tube; and a driving device which converts input AC power into AC power for driving a blower to supply the laser gas into the discharge tube, wherein the gas laser apparatus includes: a first estimation unit which calculates an estimate of input power to the laser power supply device by using an output current value and an output voltage value detected from the DC power supply unit and also using a DC power supply conversion efficiency which represents the efficiency of conversion from input power to output power by the DC power supply unit; a second estimation unit which calculates an estimate of input power to the driving device by using an output current value detected from the driving device; and a power calculation unit which calculates a power consumption value of the gas laser apparatus, based on the estimate of the input power to the laser power supply device and the estimate of the input power to the driving device, wherein when the blower is in a deceleration operation mode, the second estimation unit calculates the estimate of the input power to the driving device in accordance with a cubic function whose variable is the time elapsed from the initiation of deceleration of the blower.