An optical device 50 including a hologram recording medium 55 that can reproduce an image of a reference member and an irradiation unit that emits a coherent light beam to the optical device 50. The irradiation unit 60 includes a light source for emitting a coherent light beam and a scanning device 65 capable of adjusting a reflection angle of the coherent light beam emitted from the light source and that makes a reflected coherent light beam scan the hologram recording medium. The light source has light sources for emitting coherent light beams having different wavelength ranges. The hologram recording medium 55 has a plurality of recording areas to be scanned with a plurality of coherent light beams reflected by the scanning device 65, respectively. Each of the plurality of recording areas has an interference fringe that diffracts a coherent light beam of the corresponding wavelength range.