To provide a laser apparatus, in which diffraction light of a high order can be blocked by a simple structure when a DOE is used to branch a laser beam.

A laser processing apparatus for processing a work-piece by irradiating the same with a laser beam comprises: a work table 2; a laser beam output section 15 for outputting a laser beam; a DOE 34 for branching the laser beam from the laser beam output section 15 into a plurality of laser beams; a condenser lens 201 for condensing the laser beams from the DOE 34; a shielding plate 202 disposed between the condenser lens 201 and the work table 2 for shielding a laser beam of the DOE 34 at a predetermined or higher order; and a relay lens 203 for condensing the laser beam having passed through the shielding plate 202, on the work-piece.