The project of the invention is to provide a method for continuously manufacturing polarization diffraction elements having excellent economic performance and optical characteristics, and a polarization diffraction element manufactured by the method. The polarization diffraction element, on at least one surface of a substrate (a) made of transparent resin (A), is stacked with in sequence a layer (B) having molecular orientation capability, a layer (LC) provided with a concave part and a convex part continuously, and having a structure unit from a compound (C), and a layer (LD) having a convex part and a concave part embedded with the concave part and the convex part of the layer (LC), and having a structure unit from a compound (D); the layer (LC) has optical anisotropy, and the layer (LD) has optical isotropy.