A norbornene-based polymer contains at least one kind of a repeating unit represented by the following formula (I): ##STR00001## wherein R.sup.1 and R.sup.2 each represent a hydrogen atom, an alkyl group which may possess a substituent group or an aryl group which may possess a substituent group, L and L' each represent a bivalent linking group or a single bond, and A and A' each represent an aromatic group.