To provide a curable composition capable of obtaining a cured product which has a high Abbe number, is excellent in transparency and crack resistance, and is capable of suppressing a decrease in transparency over a long period of time; and such a cured product. This curable composition comprises solid silica fine particles A, of which an organic component is at most 5 mass % and the median diameter is from 5 to 20 nm, (meth)acrylate B which has an alicyclic condensed ring, and of which the glass transition temperature of the homopolymer is from 90 to 350° C., epoxy(meth)acrylate C which has no aromatic ring, and in which the amount of substance of ethylenically unsaturated groups is from 0.1 to 3.0 mmol/g (but excluding the (meth)acrylate B), urethane(meth)acrylate D having no aromatic ring (but excluding the (meth)acrylate B and the epoxy(meth)acrylate C), an antioxidant, and a polymerization initiator, wherein said antioxidant comprises an antioxidant having a phenol moiety and an antioxidant having a sulfide moiety (but excluding the antioxidant having a phenol moiety), in the total of the solid silica fine particles A, the (meth)acrylate B, the epoxy(meth)acrylate C and the urethane(meth)acrylate D, the solid silica fine particles A are from 3 to 55 mass %, the (meth)acrylate B is from 3 to 70 mass %, the epoxy (meth)acrylate C is from 10 to 80 mass %, and the urethane(meth)acrylate D is from 0 to 60 mass %, and to 100 parts by mass in total of the solid silica fine particles A, the (meth)acrylate B, the epoxy(meth)acrylate C and the urethane(meth)acrylate D, the antioxidant is from 0.1 to 10 parts by mass, and the polymerization initiator is from 0.1 to 10 parts by mass.