To provide a cyclic olefinic polymer which has low birefringence, excellent mechanical characteristics, precision moldability, moisture resistance (low water absorption), and the like, is especially free from even a slight color, and has extremely high transparency.

This cyclic olefinic polymer characterized by comprising the copolymer of a 2 to 20C α-olefin with a cyclic olefin having a specific structure and having a light transmittance of ≥85% at 400 nm, when a 3 mm-thick molded product of the polymer is measured. The preferable cyclic olefinic polymer is obtained by hydrogenating a polymer selected from an α-olefin cyclic olefin random copolymer obtained by copolymerizing the 2 to 20C α-olefin with the cyclic olefin, and its graft-modified products.