To prevent a non-metallic work from being burnt in the rear side by providing a laser beam attenuation member in the scrap receiver and thereby preventing upward reflection of the divergent laser beam after penetration of the work.

In laser beam cutting, a divergent laser beam LB that is diverged and emitted downward from a work W hits the bevel of the rib in the lath net comprising a laser beam attenuation member 29 and is reflected in the bottom direction of the scrap receiver 25. Then, the laser beam LB reflected by the rib of the lath net is again reflected by the lath net in the lower part, reflection thus is repeated and strength is rapidly attenuated. Consequently, the divergent laser beam LB diverged and emitted downward from the work W is prevented from being reflected upward from the scrap receiver 25 and from emitted again to the rear face of the work W. In addition, danger is also eliminated that the beam is reflected in a space without the work W, hitting the skin or the eyes of an operator and causing a burn or loss of eyesight.