A resin composition includes a resin or a resin precursor, and a nitrogen-containing aromatic heterocyclic compound. The nitrogen-containing aromatic heterocyclic compound has a structure represented by the following general formula (1), the following general formula (6) or the following general formula (7):




In the general formula (1), A1 and A2 each represent a 6-membered nitrogen-containing aromatic heterocyclic ring together with a nitrogen atom, and the 6-membered nitrogen-containing aromatic heterocyclic ring optionally forms a fused ring; and L represents a single bond, or a linking group derived from an aromatic hydrocarbon ring, an aromatic heterocyclic ring, or an alkyl group. The resin composition includes the nitrogen-containing aromatic heterocyclic compound in a range from 0.10 to 30% by mass relative to the resin or the resin precursor.