A first light source module 20 includes a light source-side connection hole portion 37 to which a irradiation-side connection portion 51, 71 of a irradiation module 50, 70 is mechanically detachably attached. The light source-side connection hole portion 37 is made common to the first irradiation-side connection portion 51, which is mounted in the first irradiation module 50, and the second irradiation-side connection portion 71, which is mounted in the second irradiation module 70, such that the light source-side connection hole portion 37 is connectable to the first irradiation-side connection portion 51 and the second irradiation-side connection portion 71.
