A process for producing microspheres, characterized by: adding a polymer solution comprising a drug, an in vivo degradable polymer, and a water-miscible good solvent (solvent (A)) for the polymer to a homogeneous liquid mixture comprising a solvent (solvent (B)) which is a poor solvent for the polymer and is miscible with the solvent (A) and a solvent (solvent (C)) which is a poor solvent for the polymer and is immiscible with the solvent (A); emulsifying the resultant mixture to prepare an emulsion in which the polymer solution forms a dispersed phase and the homogeneous liquid mixture forms a continuous phase; and removing the solvent (A) from the dispersed phase.
