Provided 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 a cosmetic using the aforesaid microparticles of a polylactic acid based resin. The method 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 type organic solvent (C) applying a shear force thereto to form an emulsion and then contacting the emulsion with a poor solvent of the polylactic acid based resin (A). According to this production method 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 smooth surfaced microparticles of the polylactic acid based resin said microparticles having a fusion enthalpy less than 5 J/g having a spherical form and showing a narrow particle diameter distribution can be provided.
