The present invention is a hydrogenated cycloolefin ring-opening polymer comprising a repeating unit derived from tetracyclododecene, and a repeating unit derived from an additional norbornene-based monomer, the hydrogenated cycloolefin ring-opening polymer having a racemo diad ratio of 65% or more with respect to the repeating unit derived from tetracyclododecene, the hydrogenated cycloolefin ring-opening polymer having a weight average molecular weight (Mw) of 10,000 to 40,000, and a resin formed article obtained by forming the hydrogenated cycloolefin ring-opening polymer having a glass transition temperature of 140 to 165° C., a melt flow rate of 8 g/10 min or more as measured at a temperature of 280° C. under a load of 21.18 N, and a flexural strength of 60 MPa or more as measured by a flexural test at a test speed of 2 mm/min, and a resin formed article, and an optical member.