A process of producing polylactic acid-based resin microparticles includes a dissolving process that forms a system, which can cause phase separation into two phases of a solution phase mainly composed of polylactic acid-based resin (A) and a solution phase mainly composed of polymer (B) different from polylactic acid-based resin, by dissolving the polylactic acid-based resin (A) and the polymer (B) different from polylactic acid-based resin in an ether-based organic solvent (C), an emulsion-forming process that forms an emulsion by applying a shear force to the system, and a microparticle-forming process that precipitates polylactic acid-based resin microparticles by contacting the emulsion with a poor solvent which has lower solubility of the polylactic acid-based resin (A) than the ether-based organic solvent (C).
