PURPOSE: To make it possible to suppress an increase in cost even if the number of laser beam heads is increased by optically branching the laser beam cast from a laser oscillator commonly used for ≥2 pieces and respectively supplying these beams to the respective laser heads.

CONSTITUTION: The laser beams supplied to individual beam guiding bodies 81, 80 in the respective laser heads 40 are reflected by respective reflection type or total reflection type mirrors and are introduced into the cylindrical bodies of the respective laser heads 40. The laser beams pass a lens and a work is subjected to laser beam processing in the focusing position by the lens. A chiller box 108 for cooling the laser oscillator 100 is arranged below a table 10.