PURPOSE: To obtain a highly sensitive, actinic radiation-curable ink composition excellent in curability, acid resistance, solvent resistance and heat resistance by mixing an actinic radiation-curable resin of a specified composition with a photopolymerization initiator as essential components.

CONSTITUTION: An oxirane compound of formula I (wherein W, X, Y and Z are each H or a group of formula II) is reacted with a compound having both a group reactive with the oxirane group and a double bond, a compound having both a group reactive with an active hydroxyl group and a double bond, and a compound having a group reactive with an active hydroxyl group to produce an actinic radiation-curable resin. This resin is mixed with a photopolymerization initiator (e.g. benzoyl isopropyl ether) as essential components to produce an actinic radiation-curable ink composition. This ink composition can be desirably used for solder resists, etching resists, etc.