PURPOSE: To provide a light surface illuminated and construction in light weight, prevent cost-up even with a minor lot, facilitate assembly, and eliminate obstruction for the producibility by introducing a specific relationship between the width of the illuminated surface and the number of light sources, and arranging the distance from the edge of the illuminated surface to the light sources so as to be no more than a specified value.

CONSTITUTION: Each light source 5 is so arranged as within 20mm of the edge of the surface to be illuminated 3, even in the condition that L/2N>20, where L is the width of the illuminated surface 3 in millimeters and N is the number of light sources 5, i.e., even though the width of illuminated surface 3 per light source is larger than 40mm. Accordingly, even when ununiform reflex pattern positions on a lighting curtain 9 are out of matching with the light sources 5, unevenness in the brightness is not perceived as light unevenness due to optical illusion because the unevenness in brightness appearing on the illuminated surface in the neighborhood of the light sources 5 will also lie within 20mm of the edge of the illuminated surface 3. This arrangement, where no light guide member is used, permits lightweight construction and light surface illuminated, and also allows preventing cost-up even with a minor lot. Further because no light unevenness is perceived, no particular accuracy is required for assembly, and the producibility will not be obstructed when assembly is carried out.