An optical path changing polarizer has a polarizer including a polarizing element and a transparent protective layer disposed on at least one side of the polarizing element, an adhesive layer disposed on one side surface of the polarizer, and a repetitive prismatic structure disposed on the other side of the polarizer. The repetitive prismatic structure includes optical path changing slopes aligned in a substantially constant direction so as to be inclined at an inclination angle of from 35 to 48 degrees with respect to a plane of the polarizer. Each of respective refractive indexes of the adhesive layer and a material for forming the optical path changing slopes is not lower than a refractive index of the polarizing element or the transparent protective layer. The adhesive layer has a refractive index different by 0.1 or less from a refractive index of a surface layer of the one side of the polarizer.