From the point of view of obtaining linearly polarized light in a wide wave range of the visible light, or the like, it is possible to use a polyvinyl alcohol film made of a polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol, the film being oriented and aligned after impregnated with iodine or/and a dichromatic dye such as an azo dye, an anthraquinone dye, a tetrazine dye,