The present invention provides a vinyl polymer with an epoxy group terminally
introduced therein and an epoxy resin composition comprising (A) an epoxy resin
and (B) a vinyl polymer which has a main chain produced by living radical polymerization
and has a reactive functional group at a main chain terminus. A flexible epoxy
resin composition can be obtained using these compounds. The invention further
provides an epoxy resin composition having an epoxy group at a main chain terminus thereof.