PURPOSE: To provide a titled device which works simply, easily and uniformly the surface of a material to be worked by the constitution in which laser light is made incident to an integrating sphere and the laser light having uniform intensity is outputted from at least one output port of the integrating sphere.

CONSTITUTION: The laser light 2 outputted from a laser oscillator 1 is made incident to an integrating sphere 9 through an inlet port 10. The laser light 2 made incident in the sphere 9 is uniformly diffused by the repetitive irregular reflection on the inside surface formed to the rugged shape in said sphere 9 and laser light 12 having a uniform intensity distribution is outputted through an outlet port 11. The light 12 is condensed by a lens 4 and is irradiated to a material 5 to be worked consisting of a metal by which a surface treatment such as hardening or the like is accomplished with good quality at a specified depth.