The purpose of the present invention is to provide: a method for producing a sustained-release drug that makes it possible to load a medicinal ingredient on a porous material comprising a bioabsorbable polymer and control the release rate of the medicinal ingredient and a sustained-release drug. The present invention is a method for producing a sustained-release drug that includes: a solution preparation step in which a medicinal ingredient-bioabsorbable polymer solution containing a uniformly dispersed medicinal ingredient and a dissolved bioabsorbable polymer is prepared using a biabsorbable polymer, a medicinal ingredient, a solvent 1 which is a poor solvent having low solubility with respect to the bioabsorbable polymer, a solvent 2 which is a good solvent having high solubility with respect to the bioabsorbable polymer and which is not miscible with the first solvent 1, and a cosolvent 3 which is miscible with the first solvent 1 and the second solvent 2 a precipitation step in which the medicinal ingredient-bioabsorbable polymer solution is cooled and a porous material comprising bioabsorbable polymer that contains the medicinal ingredient is precipitated and a freeze drying step in which the porous material comprising bioabsorable polymer that contains the medicinal ingredient is freeze dried in order to obtain a sustained-release drug comprising a porous material loaded with the medicinal ingredient. The release rate of the medicinal ingredient of the obtained sustained-release drug is controlled by using one or more types of the cosolvent 3 and adjusting the type and blending ratio of the cosolvent 3.La présente invention a pour objet de réaliser : un procédé de production dun médicament à libération prolongée qui permet de charger un ingrédient médicamenteux sur un matériau poreux comprenant un polymère bioabsorbable, et de réguler la vitesse de libération de lingrédient médicamenteux et un médicament à libération prolongée. La présente invention concerne
