It is an object of the present invention to provide a solid dispersion, which suppresses a reduction in the content of an active ingredient caused by oxidation or decomposition of rapamycin or a derivative thereof, can ensure long-term stability, and has high safety. According to the present invention, there is provided a method for producing a solid dispersion comprising, as an active ingredient, rapamycin or a derivative thereof, wherein the method comprises: a first step of mixing a first solvent that is a protic polar solvent, a second solvent that is an aprotic solvent, a water-soluble polymeric carrier, and rapamycin or a derivative thereof, wherein the ratio of the first solvent is higher than 50% by volume of the total volume of the first solvent and the second solvent； and a second step of removing the solvents.
