Effects of a pressurized spark switch on N2laser output have been observed optically with quartz fibers. The output power increased with decreasing the gap of the spark switch while keepingpgd=0.51 kg/cm (pgis the N2gas pressure in the spark switch anddis the gap distance) andpN2=40 Torr (pN2is the pressure of the laser medium gas). One nanosecond pulses with peak powers of 120 kW have been generated for the first time for low‐pressure operating N2lasers.