A microencapsulated hardener for epoxy resins which comprises cores comprising an epoxy-resin hardener and shells covering the cores, characterized in that the epoxy-resin hardener comprises as a major component an amine adduct obtained by the reaction of an epoxy resin (e1) with an amine compound, the epoxy-resin hardener has an overall amine value of 370 to 1,000, the epoxy-resin hardener has an average particle diameter of 0.3-12 µm, excluding 0.3 µm, and the shells have, on at least the surface thereof, a combined group (x) that absorbs infrared rays having a wavenumber of 1,630-1,680 cm-1, a combined group (y) that absorbs infrared rays having a wavenumber of 1,680-1,725 cm-1, and a combined group (z) that absorbs infrared rays having a wavenumber of 1,730-1,755 cm-1.