NOVELTY - A water-soluble polypeptide and surfactant are dissolved in water to obtain water phase. The obtained water phase and oil phase are emulsified to obtain oil-in-water-type emulsion. Interfacial polymerization of polyfunctional isocyanate compound is carried out, and porous resin particles are formed. An enzymatic decomposition process of the obtained porous resin particles is carried out by adding protease. The porous resin particles are collected, and mixed with imidazole-compound solution to obtain latent hardener.    USE - Manufacture of latent hardener used for thermosetting resin composition used for anisotropic electroconductive adhesive film for solar cell (both claimed).    ADVANTAGE - The method effectively provides latent hardener. The thermosetting resin composition using latent hardener has excellent low-temperature rapid-hardening property.    DETAILED DESCRIPTION - A water-soluble polypeptide and surfactant are dissolved in water to obtain water phase. A polyfunctional isocyanate compound is dissolved in 4.5-7.5 times of organic solvent to obtain oil phase. The obtained water phase and oil phase are emulsified to obtain oil-in-water-type emulsion. Interfacial polymerization of the polyfunctional isocyanate compound is carried out in oil phase, and porous resin particles are formed by heating oil-in-water-type emulsion and volatilizing organic solvent. An enzymatic decomposition process of the obtained porous resin particles is carried out by adding protease. The porous resin particles are collected from the interfacial-polymerization reaction liquid, and mixed with imidazole-compound solution obtained by mixing imidazole compound in organic solvent. The imidazole compound solution is permeated into 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 film-forming.