To provide an illumination instrument that can perform more uniform illumination using as a light source an LED lamp or the like having a strong directivity with scarce efforts of repair and check and can be produced with an excellent endurance and a low cost.

It arranges a light source body (2) such as an LED lamp into an opening end (1b) of a light transferring member (1) in the shape of a transparent or a semitransparent can and generates light into an axis direction (S) of the light transferring member. It arranges a transparent or semitransparent type of a protrusion forming body (4) on an inner circumference surface (1c) of the light transferring member. Protruding parts (4a) not only are made to protrude toward an inner part of the light transferring member from the protrusion forming body but also are interspersed. The light from the light source body is diffused with reflection by contacting these protruding parts, thereby giving more uniform illumination light into an outer circumference surface of the light transferring member making up a light taking-out surface.