A photocurable and thermosetting resin composition comprises (A) an actinic
energy ray-curable resin having at least one structure represented by the
following general formula (1), (B) a polymerization initiator, (C) a
diluent, and (D) a polyfunctional oxetane compound. The actinic energy
ray-curable resin mentioned above can be produced by causing the reaction
of (a) a polyfunctional oxetane compound with (b) an unsaturated
monocarboxylic acid and the subsequent reaction of (c) a polybasic acid
anhydride with a primary hydroxyl group of the resultant modified oxetane
resin (a').
##STR1##
wherein R.sup.1 represents a hydrogen atom or an alkyl group of 1 to 6
carbon atoms, R.sup.2, R.sup.3 and R.sup.4 independently represent a
hydrogen atom, an alkyl group of 1 to 6 carbon atoms, an aryl group, an
aralkyl group, a cyano group, a fluorine atom, or a furyl group, and X
represents a polybasic acid anhydride residue.
