NOVELTY - A water phase is emulsified with oil phase to obtain oil-in-water-type emulsion. The polyfunctional isocyanate compound in oil phase is subjected to interfacial polymerization. A protease is injected to interfacial-polymerization reaction liquid. The processed porous resin particles are collected from the reaction liquid. The collected porous resin particles are mixed with imidazole compound solution. The imidazole compound solution is permeated to the porous resin particles, and the imidazole compound is held inside the porous resin particles, to obtain latent hardener.    USE - Manufacture of latent hardener used for thermosetting resin composition for anisotropic electroconductive adhesive film, adhesive film for solar cell (all claimed), and electronic components e.g. integrated circuit chip.    ADVANTAGE - The method provides thermosetting resin composition having excellent low-temperature rapid-hardening property.    DETAILED DESCRIPTION - A water phase formed by dissolving water-soluble polypeptide and surfactant in water is emulsified with oil phase formed by dissolving polyfunctional isocyanate compound in organic solvent to obtain oil-in-water-type emulsion. The polyfunctional isocyanate compound in oil phase is subjected to interfacial polymerization by heating the oil-in-water-type emulsion to form porous resin particles. A protease is injected to interfacial-polymerization reaction liquid in which porous resin particles are dispersed, and the porous resin particles are subjected to enzymatic decomposition process. The enzymatic decomposition-processed porous resin particles are collected from the interfacial-polymerization reaction liquid. The collected porous resin particles are mixed with imidazole compound solution formed by dissolving an imidazole compound in an organic solvent. The imidazole compound solution is permeated to the porous resin particles, and the imidazole compound is held inside the porous resin particles, to obtain latent hardener. INDEPENDENT CLAIMS are included for the following:    (1) thermosetting resin composition, which contains latent hardener and thermosetting resin; and    (2) anisotropic electroconductive adhesive film, which is formed by dispersing electroconductive particles in thermosetting resin composition and forming film using the resin composition.