A photo-curable resin composition suitable as a material for optical molding. The composition can produce cured products with excellent mechanical strength and high heat resistance. Further disclosed is a process for molding a resin-based mold which provides superior molding dimensional precision and superb repetition durability. The composition contains a monomer component which contains (A) 20-80 wt % of a urethane-bond polyfunctional (meth)acrylate having a number average molecular weight of 1,000 or less and (B) 80-20 wt % of an ethylenically unsaturated monomer containing a cyclic structure and at least one ethylenically unsaturated bond in the molecule and of which the homopolymer has a glass transition temperature of 50.degree. C. or higher; (C) a photopolymerization initiator; and (D) an inorganic filler having an average particle diameter or an average fiber length of 1-50 .mu.m, wherein the ratio of the inorganic filler for 100 parts by volume of said monomer components and the photopolymerization initiator is 100-160 parts by volume, and the heat distortion temperature of the cured resin produced from the photo-curable resin composition is 80.degree. C. or higher.