To remarkably improve the light emitting luminance by laminating a transparent layer comprising a surface which reflects the total light excluding a ray of light of which an angle of incidence is rectangular, and forming a groove of which the side walls at both sides are opposite to a bottom part on the surface, a reflection body mounted on the bottom part, and a fluorescent layer mounted on a rear face of the transparent layer.

A rear face of a transparent layer 12 is laminated on a surface of a fluorescent layer 11. A surface of the transparent layer 12 comprises a groove 13. The side walls 13a at both sides of the groove 13 are opposite to a bottom part 13b of the groove 13. That is, by forming the above-mentioned groove 13, the transparent layer 12 is provided with a pair of edge parts 12a, 12a opposite to each other through an opening 13c of the groove 13. When a ray of light is not irradiated to a phosphor 10 at night, the optical energy accumulated in the fluorescent layer 11 is excited, and the light is emitted outward. The light collected in the edge parts 12a of the transparent layer 12 is reflected by a reflection body 14 to be radiated outward, so that the luminance can be remarkably improved.