PROBLEM TO BE SOLVED: To provide a type II collagen production promoter having effectiveness and high safety.SOLUTION: The subject matter characteristically includes an Astilbe thunbergii extract. For its preparation form, various forms can be selected. Its dose varies by intended use, age, weight, symptom, therapeutic effects or the like, preferably 0.02-20 mg/kg body weight, particularly preferably 0.1-10 mg. The subject matter is useful for drugs, quasi drugs, foods and the like to prevent and improve decreased cartilage tissues.