PURPOSE: To obtain the title compsn. providing a cured product with excellent acid resistance, alkali resistance, etc., being developable with an aqueous weak alkali soln. and having excellent sensitivity by incorporating a specified energy ray-curable resin and a photopolymn. initiator as essential ingredients.

CONSTITUTION: An energy ray-curable resin of formula I {wherein X is O or CH2; R is H or CH3; Y is a group of formula II (wherein R1 is R; R2 is R, CN or a halogen; B1 is a residue of a polybasic acid anhydride); at least one of Zs is a group of formula III [wherein A is a residue of a compd. having a (meth)acryloyl group] and the rest of Zs are each a group of formula II, III or IV} and a photopolymn. initiator (e.g. benzoin isopropyl ether) are incorporated.