A clear image can be achieved by preventing dusts from collecting in grooves formed in a transparent substrate and by improving contrast as well. A film is provided in such a manner as to cover a light reflection pattern formed in the surface of the transparent substrate. The film is sealingly fixed to the transparent substrate for preventing dusts from entering the light reflection pattern (particularly the grooves) during the process of assembling the spread illuminating apparatus. Also, the surface of the transparent substrate can be protected from scratches thanks to the film fixed. The amount of interface reflection can be reduced by using resin or the like as the film material, and contrast can be improved by setting the thickness of the film to a value smaller than prescribed.