In producing microcapsules using the amino resin as a capsule wall in a system in which hydrophobic core material is dispersed or emulsified in an aqueous acidic solution containing an anionic colloidal substance, said anionic colloidal substance comprises an anionic, water-soluble copolymer consisting of at least three monomers including acrylic acid, hydroxyalkylacrylate or hydroxyalkylmethacryl