Laser beam processing machine

A laser beam processing machine comprising a chuck table for holding a workpiece and a laser beam application means for applying a pulse laser beam capable of passing through the workpiece to the workpiece held on the chuck table, the laser beam application means comprising a pulse laser beam oscillation means and a transmitting/converging means including an optical transmission means for transmitting a pulse laser beam oscillated by the pulse laser beam oscillation means and having one condensing lens for converging the pulse laser beam transmitted by the optical transmission means, wherein

• the optical transmission means comprises a path distribution means for distributing the pulse laser beam oscillated by the pulse laser beam oscillation means to a first path and a second path alternately, a plurality of mirrors and a plurality of beam splitters for aligning an optical axis of a laser beam that has been distributed by the path distribution means and passes through the first path with an optical axis of a laser beam that has been distributed by the path distribution means and passes through the second path by the path distribution means again, and a focusing point depth displacing means that is arranged in any one of the first path and the second path and displaces the focusing point of one of the laser beams, which passes through one of the paths and is converged by the condensing lens, in the direction of the optical axis;
• and
• one laser beam that passes through one of the paths and is converged by one condensing lens and the other laser beam passing through the other path and is converged by the condensing lens are applied at different focusing points which have been displaced from each other in the direction of the optical axis, alternately with a time lag between them.