TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The curing agent (D) is chosen from carboxylic compound, sulfonic acid compound, urea compound, isocyanate compound, and epoxy resin (e1). The content of low-molecular amine compound (G) is 0.5-35 parts mass with respect to 100 parts mass of curing agent (D). The nitrogen-containing heterocyclic compound (C) is chosen from pyridine derivative, pyrimidine derivative, pyrazine derivative, triazine derivative, quinoline derivative, isoquinoline derivative and purine derivative, preferably pyridine derivative. Preferred Process: The amine adduct (E) is obtained by reacting epoxy resin (e1) or isocyanate compound (N1), and 1-15C amine compound (a2). Preferred Properties: The ratio of weight average molecular weight and number average molecular weight of amine adduct (E) is 1-7.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The epoxy resin composition further comprises epoxy resin curing agent (D) having average particle diameter of more than 0.3-12 mu m, as core of the component (B), amine adduct (E) obtained using amine compound (a1), amine adduct (F) having tertiary amino group, low-molecular amine compound (G) having tertiary amino group, thermosetting resin (H) chosen from oxetane resin, mono-epoxy resin and polyvalent epoxy resin, and epoxy resin curing agent (h3) chosen from acid anhydride-type curing agent, phenol-type curing agent, hydrazide-type curing agent, guanidinium-type curing agent and thiol-type curing agent. The microcapsule-type latent hardener (B) has core structure covered with shell (S) containing synthetic resin and/or inorganic oxide on the surface. The content of microcapsule-type latent hardener (B) is 1-300 parts mass with respect to 100 parts mass of epoxy resin (A). Preferred Process: The shell (S) comprises reaction product obtained by reacting isocyanate compound, activated hydrogen compound, epoxy resin curing agent (h2), epoxy resin (e2), and low-molecular amine compound.