It is an object of the present invention to provide a chondrogenesis promoter that is safe and exhibits a chondrogenesis-promoting effect by daily ingestion. It is also an object of the invention to provide a proteoglycan synthesis promoter that exhibits a proteoglycan synthesis-promoting effect by ingestion. Provided are a chondrogenesis promoter and a proteoglycan synthesis promoter each containing a milk-derived basic protein fraction as an active ingredient. Synthesis of proteoglycan and formation of a cartilage can be promoted by oral ingestion of the milk-derived basic protein fraction. A hydrolysate of the milk-derived basic protein fraction also has a similar chondrogenesis-promoting effect.
