To provide a polymer composition excellent in light resistance and transparency, and capable of giving a molded article that is controlled from deterioration of optical characteristics when violet laser light is used as light source, and to provide a molded article such as optical parts etc. obtained by molding the polymer composition, and optical pickup devices using the optical parts.

The polymer composition includes a polymer that has an alicyclic structure at least in one part of repeated structural unit thereof, and whose iron atom content is not more than 100 ppb, and the molded articles such as optical parts etc. are obtained by molding the polymer composition, and the optical pickup devices are made by using the optical parts.