PURPOSE: To obtain at a low cost the optical refractive layer having nessesary optical refractivity by laminating three or more layers of the unit optical refractive resin layers consisting of the resin material containing a dye and a resin material having a prescribed value of the real number parts of complex refractive index, and consisting of high and low refractive index layers on the light- transmissive substrate forming a pregroup.

CONSTITUTION: The soln. dissolving a cyanine dye in ethylcellosolve is applied on the substrate 2 made of light-transmissive polycarbonate which forms spiral pregroup 7, and a high refractive index layer 5 is formed. The soln. dissolving a polyolefin in ethylcyclohexane is applied on the layer 5 and a low refractive index layer 6 is formed. The real number parts of the complex refractive indexes of the layer 5 and 6 are above 2.0 ndye at the layer 5 and below 1.6 nenh at the layer 6. The optical refractive resin layer 3 is formed by laminating three or more layers of the unit optical refractive resin layer 3A consisting of the layer 5 and 6, and a protective layer 4 is formed on the layer 3. In this way, nessesary optical refractivity is secured and can be produced at a low cost without providing a metallic optical refractive layer.