A lactulose-containing powder composition is produced by preparing a raw material liquid so that a lactulose content within a powder produced following spray drying is 10 to 50% by weight, a protein content is 0.2 to 9.0 parts by weight per 1 part by weight of lactulose, and a chlorine content is no more than 0.08 parts by weight per 1 part by weight of protein, and subsequently subjecting this raw material liquid to spray drying.