To make light from a light source enter a light guiding plate as much as possible and make light beam emit from an optional part of an emission surface of the light guiding plate at designated optional emission angles.

The light guiding body 2 includes a surface part 3 emitting light from a light source 20, a back surface part 6 on an opposite side of the surface part 3, and a side surface part 4 put between the surface part 3 and the back surface part 6. An entrance end surface part 5 guiding light from the light source 20 is smaller than the surface part 3, the back surface part 6 and the side surface part 4. The side surface part 3 is twisted wholly or partially. Fine projection and dent shapes, prisms and fine grooves or the like are selectively wholly or partially provided on the surfaces except the entrance end surface part 5 and surface part 3. A reflector 7 reflects light leaking from the light guiding body 2 to the light guiding body 2 and a light guiding plate 9. The light guiding plate 9 is comprised of an entrance surface part 12 guiding emission light form the light guiding body 2, a surface part 10 having larger area than the entrance surface part 12 and emitting light form the entrance surface part 12, and a back surface part 11 on an opposite side of the surface part 10.