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