PROBLEM TO BE SOLVED: To provide a stabilization method of eye drops containing allantoin, cyanocobalamin, and optionally other active ingredients, and to provide stabilization eye drops containing allantoin, cyanocobalamin, and optionally other active ingredients.SOLUTION: Stable eye drops containing allantoin and cyanocobalamin, which are unstable active ingredients, and optionally other active ingredients can be provided by controlling pH of eye drops to be in a specific range, controlling a content of allantoin in eye drops to be in a specific range, controlling a content of sodium chondroitin sulfate and glycyrrhizinate dipotassium to be in a specific range, and adding benzalkonium chloride and a specific amount of chlorobutanol as antiseptics while controlling a content of nonionic surfactant.