A discharge excitation gas laser device includes: first and second discharge electrodes disposed to face each other; a plurality of peaking capacitors connected to the first discharge electrode; a charger; a plurality of pulse power modules, each one of the pulse power modules including a charging capacitor to which a charged voltage is applied from the charger, a pulse compression circuit that pulse-compresses and outputs electrical energy stored in the charging capacitor as an output pulse to a corresponding peaking capacitor, and a switch disposed between the charging capacitor and the pulse compression circuit; a plurality of output pulse sensors, each one of the output pulse sensors detecting an output pulse output by a corresponding pulse power module; and a control unit configured to control, based on a detection result of each of the output pulse sensor, a timing of a switch signal to be input to a corresponding switch.