A curable composition includes (A) a (meth)acrylate, (B) a radical polymerization initiator, (C) an epoxidized polyisoprene containing an epoxy group at 0.15 to 2.5 meq/g in the molecule and having a number-average molecular weight of 15000 to 200000, and (D) a curing accelerator. The curable composition shows high elongation and excellent rubber elasticity even in a cured state and has superior compatibility, transparency, waterproofness and flexibility, so that cracks and separation of cured products are reduced. Accordingly, the composition is suitable for use as adhesives, coating agents, encapsulating materials, inks, sealing materials and the like.