To provide an optical form excellent in low birefringence and low in water absorption.

A spiro ring-containing norbornene derivative of the formula(1) ( wherein, R1 and R2 are each H, a 1-20C hydrocarbon group or a group containing halogen atom(s), silicon atom(s), oxygen atom(s) or nitrogen atom(s); Z is a 3-10C bivalent hydrocarbon group optionally having polar group as substituent; and n is 0 or 1 ) is provided. A norbornene-based ring-opened polymer therefrom, a hydrogenated product of the polymer, an optical resin material comprising the hydrogenated product, and the optical form obtained by forming the optical resin material, are also provided, respectively.