To obtain an antireflection film consisting of a small total number of layers and having high performance specially in a UV range, a small optical loss and high laser light resistance by forming a 1st antireflection layer on a substrate by a wet or dry process and a 2nd antireflection layer on the 1st layer by a wet process.

A 1st antireflection layer 16 of a 1st material is formed on a substrate 12 by a wet or dry process and a 2nd antireflection layer 20 of a 2nd material coating the 1st layer 16 is formed by a wet process to obtain the objective two-layered antireflection film. The 1st layer (lower layer) 16 is preferably formed by the dry process because production time and cost are reduced. The 2nd layer 20 is formed by the wet process so as to ensure the desired refractive index.