Abstract: An unsaturated monocarboxylic ester compound has at least two structures represented by the following general formula (1): wherein R1 represents a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, and R2, R3 and R4 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. A curable composition comprises (A) the unsaturated monocarboxylic ester compound having two or more structures represented by the general formula (1) mentioned above, (B) a polymerization initiator, and optionally (C) a diluent.