In a laser processing machine, a laser control system includes a photo detector (21) detecting intensity of light generated by laser-induced plasma produced by applying laser beams on an object, and a control unit (30) for controlling a laser pulse signal to have an optimum pulse width and optimum pulse period effective in each pulse signal based on the detection signal, so that the optimized laser pulse signal is obtained to thereby automatically control the generation of the laser beams, where the pulse width of each pulse is controlled by the control unit (30) so that the detection signal outputted from the photo detector (21) has its peak values to be all equal to a constant level (Vp), and the pulse period of each laser pulse signal is so controlled as to have a reference threshold level (Vr) which is previously given by the material of the object, and thus the total processing time in perforating process can be remarkably reduced.