A cyclic conjugated diene copolymer comprising a main chain comprised of (A) cyclic conjugated diene monomer units, (B) monomer units obtained from vinyl aromatic monomers each having a hydrogen atom at the -position thereof, and optionally (C) monomer units obtained from commoners which are other than the monomers used for obtaining the monomer units A and B and which are copolymerizable with at least one of the monomers used for obtaining the monomer units A and B, wherein all monomer units A and the monomer units B together form one or more polymer chains each having an A/B random sequence, wherein the one or more polymer chains each having an A/B random sequence contain at least one polymer chain having a number average molecular weight of from 20,000 to 500,000 and contain no polymer chain having a number average molecular weight of more than 500,000. A process for producing the above-mentioned cyclic conjugated diene copolymer by living anionic polymerization.