The present invention is intended to provide a technique for delaying timing for releasing an agricultural chemical compound from a microcapsule formulation which contains the agricultural chemical compound in at least one compound from the group of consisting of ester compounds and aromatic hydrocarbon compounds. A microcapsule formulation produced by the following process is more effectively controlled in release of an agricultural chemical compound therefrom, than any of the existing microcapsule formulations. This production process comprises the steps of(1) maintaining a mixture of an agricultural chemical compound (a), at least one compound (b) selected from the group consisting of ester compounds and aromatic hydrocarbon compounds, except for the compounds of the formula (I):(wherein X represents —CH2—CH2— or —CH═CH— R1 represents a C1-C4 alkyl group and R2 represents a C1-C4 alkyl group), and a polyisocyanate (c) at a temperature of from 20 to 80° C. for 3 hours or longer(2) adding the resulting mixture to an aqueous solution which contains a polyol or a polyamine, to form liquid droplets of the mixture in the aqueous solution(3) forming coatings of a polyurethane or a polyurea around the liquid droplets.
