Abstract: A photocurable and thermosetting resin composition developable with an aqueous alkali solution is disclosed. The composition comprises in combination: (A) a photosensitive prepolymer soluble in a dilute aqueous alkali solution obtained by esterifying an epoxy resin represented by the following general formula (1) with (meth)acrylic acid and further adding an acid anhydride thereto until an acid value reaches a level in the range of 60 to 120 mg KOH/g, (B) a diglycidyl ether type epoxy compound containing two epoxy groups in the molecular unit thereof, (C) a photopolymerization initiator, and (D) a diluent at such ratios of combination that said epoxy compound (B) accounts for a proportion in the range of 5 to 120 parts by weight and said photopolymerization initiator (C) for a proportion in the range of 0.1 to 30 parts by weight, based on 100 parts by weight of said photosensitive prepolymer (A): ##STR1## wherein X represents CH.sub.2, C(CH.sub.3).sub.2, or SO.sub.