An optical beam emitted from a laser light source is converted by a spatial filter to have a desired beam diameter, and converted by a collimate lens into a collimated beam. The optical beam rendered to be a collimated beam has its intensity adjusted by an ND filter. The optical beam having its intensity adjusted is lead by a mirror to an angle rotation mirror. The angle rotation mirror reflects the optical beam toward a hologram element. Holograms are recorded on the hologram element in advance, so that reconstructed beams are collected at a prescribed position irrespective of an incident position of the optical beam.