PROBLEM TO BE SOLVED: To implement both switching of an irradiation lights wavelength band and acquisition of an observation image having higher quality.SOLUTION: There is provided a lighting device comprising: a first light source unit for emitting white light a second light source unit for emitting laser light with a plurality of predetermined wavelength bands included in a wavelength band of the white light a diffusion member for generating a secondary light source by diffusing the laser light emitted from the second light source unit and a dichroic mirror for multiplexing the white light emitted from the first light source unit and laser light emitted from the secondary light source. The dichroic mirror attenuates a component of the white light in the wavelength band corresponding to the laser light and multiplexes the laser light and the white light whose component in the wavelength band corresponding to the laser light is attenuated.SELECTED DRAWING: Figure 1
