An adhesive disposed between a protective cover and a sleeve member is prevented from flowing in to a position where a fluorescent body should be originally arranged. An illumination optical unit includes an optical fiber, a fluorescent body, a ferrule as a holding member holding the fluorescent body and the optical fiber, a tubular sleeve member that covers the outer periphery of the fluorescent body, and a protective cover that seals the distal end of the sleeve member. The ferrule holds the fluorescent body and is fitted into a fitting hole of the sleeve member. Since glass beads are mixed into an adhesive that bonds the protective cover to a receiving portion of the sleeve member, excessive flow of the adhesive can be suppressed.
