PURPOSE: To obtain title microcapsule which has excellent chemical stability and heat-resistant property and is not blotted with a core material by a method wherein liquid materials and powders such as colloidal CaCO3 are kneaded to obtain a paste material and the paste material is added to a bed of silica powders having a specified particle size within a stirring apparatus equipped with a cutter.

CONSTITUTION: Liquid materials (such as solvent, plasticizer), which become a core material, and powders such as colloidal CaCO3 are kneaded by a roll, a dispersing machine, etc. The paste material obtained (preferably having a viscosity of at least 500cp at 25°C) is added to a bed of silica powders having a particle size of from 1W100mμ within a stirring apparatus equipped with a cutter in a ratio of 10W 200 parts by weight of silica per 100 parts of the liquid material to obtain microcapsules. Chemical stability and heat-resistant property which silica has, are given to the produced microcapsules. They also possess stability in the shape and machanical strength. Further, it is difficult that the microcapsules are blotted with the core material.