PURPOSE: To make incident light from a light source lamp does not leak and moreover the incident area of the light from the light source lamp is broadened and the light is reflected well to a indicating plate by a method wherein an opaque back plate is provided at the back side of the transparent indicating plate and a slant surface is provided at the end of the back plate facing to the light source lamp and the slant surface is luster treated.

CONSTITUTION: The light from the light source lamp does not leak to the back of the indicating plate, because the opaque back plate 8 is provided behind the indicating plate 7 and slant surface 10 is provided at the end of the back plate facing to the light source lamp 9, and the slant surface is luster treated. Moreover, because the incident area of the light from the light source lamp 9 is broadened and light is easily reflected on the indicating plate 7, the lighting effect by the edge light method is excellent. And the light source lamp 9 is strong against a shock and the light source lamp will not break by the shock such as by the opening and shutting of a door, because the lamp 9 is holded in the elastic lamp holder 12 provided on the base plate 11.