A polarization splitting section has a structure in that a polarization splitting layer is formed of a light reflecting grid member which is arranged in a grid-shaped pattern on an optically-transparent substrate, and an optically-transparent medium is filled between the grid member and the substrate in contact with the grid member surface and the substrate surface, and the grid member and the filled optically-transparent medium are bonded to the substrate with another adhesive agent or tackiness agent formed of an optically-transparent medium interposed. The polarization splitting layer is partly protruded externally from the surfaces of prism materials.