To provide an aromatic diamine compound which is a high refractive index resin material having high processability, a polyamic acid and a polyimide resin using the same, and an optical element.

The polyamic acid and the polyimide resin are obtained by reacting a 1,5-bis(aminobenzoyl) naphthalene compound (1) represented by formula (1) (wherein R1 and R2 are each a 1-6C alkyl group) and a diamine compound containing the same with an acid dianhydride compound. The optical element comprises the polyimide resin.