An organic substrate provided with a light absorptive antireflection film, which contains an organic substrate, and a light absorbing film and a low refractive index film formed in this order on the substrate, to reduce reflection of incident light from the low refractive index film side, wherein the organic substrate has its surface plasma-treated, and a layer made essentially of at least one member selected from the group consisting of silicon, a silicon nitride, a silicon oxide and a silicon oxy-nitride, is formed between the plasma-treated substrate surface and the light absorbing film.