To provide a method for manufacturing a copolymer from an α-olefin and a cyclic olefin, using a copolymerization catalyst that is more easily synthesized for industrial use, and has a high polymerization activity and can give a high degree of copolymerization.

According to this method for manufacturing a cyclic olefin copolymer, an α-olefin and a cyclic olefin are subjected to copolymerization in the presence of a catalyst composed of a transient metal compound (A) having a one-molecule ligand comprising a specific cyclopentadienyl structure and at least one aryloxy group, and an activator (B).