LASER PROCESSING DEVICE

PROBLEM TO BE SOLVED: To provide a laser processing device which enables to make a constitution easy and simplifies an actual optical axis adjusting work by eliminating a constraint about the size around the space adjusting mirror. The device is constituted to make the beam space of the divided laser beam wide, and to make the beam space to be a desired one when the beam enters the slit. SOLUTION: A beam space changing means 8 is installed on the optical path along which each laser beam reflected by total reflection mirrors 4a-4d enters a slit 9. In this case, the beam space changing means 8 is the so-called afocal optical system and reduces the ray bundle width of the incident ray bundle. It is also functioning to narrow the beam space without changing a level of convergence, divergence or the parallelism between the beams.