Disclosed are a method for producing microparticles of a polylactic acid-based resin, porous microparticles of a polylactic acid-based resin, said microparticles having a small particle diameter, showing a high oil absorption ability and being appropriately usable for cosmetics, smooth-surfaced microparticles of a polylactic acid-based resin, said microparticles having a spherical form, showing a narrow particle diameter distribution and being appropriately usable for toners, and cosmetics using the aforementioned microparticles of a polylactic acid-based resin. The process for producing microparticles of a polylactic acid-based resin comprises: dissolving a polylactic acid-based resin (A) and a polymer (B), which is different from polylactic acid-based resins, in an ether-based organic solvent (C) applying a shear force thereto to form an emulsion and bringing the emulsion into contact with a poor solvent of the polylactic acid-based resin (A). According to this production process, it becomes possible to provide porous microparticles of the polylactic acid-based resin, said microparticles having a fusion enthalpy of the polylactic acid-based resin (A) of 5 J/g or greater, having a small particle diameter and showing a high oil absorption ability, and to provide smooth-surfaced microparticles of the polylactic acid-based resin, said microparticles having a fusion enthalpy of less than 5 J/g, having a spherical form and showing a narrow particle diameter distribution.
