Drilling in thin metal plates has been studied with two types of pulses from an ordinary flash‐lamp‐pumped Nd‐YAG laser. The drilling performance with a normal pulse consisting of a 200‐&mgr;s continuous emission preceeded by a few relaxation oscillations has been compared with that of a 200‐&mgr;s train of 0.5‐&mgr;s pulses. The pulse train was obtained by introducing a periodic low loss into the laser resonator with the frequency of the relaxation oscillations. It is shown that the use of the pulse train is much superior to the normal pulse for drilling in aluminium and similar metals.