PROBLEM TO BE SOLVED: To provide a biologically active peptide sustained-release microparticle which suppresses a rapidly increased release amount of a biologically active peptide immediately after administration, and can achieve a continuously sustained release of the biologically active peptide over a long period of time, in the biologically active peptide sustained-release microparticle obtained by dispersing the biologically active peptide into a formulation base material containing a biodegradable polymer as a principal component.SOLUTION: The invention provides a method for producing a biologically active peptide sustained-release microparticle comprising a step of mixing a biologically active peptide, a biodegradable polymer, and a solvent to prepare a solution, and a step of spray drying the solution. The solvent is a water-containing solvent containing a mixed solvent of one or more kinds of alcohols selected from methanol, ethanol, 1-propanol, 2-propanol, and tert-butanol, and one or more kinds of organic solvents selected from ethyl acetate, acetone, tetrahydrofuran, acetonitrile, and N, N-dimethylformamide, and water.
