A laser marking device (1) includes a laser light source (24) that emits a laser beam, and a beam splitter (230) receiving the laser beam and allowing a part of the laser beam to be reflected thereat and a remaining part of the laser beam to be transmitted therethorogh. The beam splitter (230) has an unpolarized film (233a, 233b) into which the laser beam is entered to divide the laser beam into a plurality of laser beams that travels in different directions, at a predetermined rate regardless of change of a polarized characteristic of the laser beam.