PROBLEM TO BE SOLVED: To stabilize folic acid which is extremely unstable to light and the like and difficult to store.SOLUTION: Folic acid is stabilized by compounding (A) folic acid with (B) one or more kinds selected from among lysine, arginine, triptophan and hydroxyproline and their salts. More suitably, (C) one or more kinds selected from among phosphoric acid, citric acid, succinic acid and lactic acid and their salts are compounded.