The present invention is related to a liquid agent containing biotin and vitamin B2, wherein the vitamin B2 is stabilized. More specifically, the present invention is related to a liquid agent containing biotin, vitamin B2 and vitamin C with the biotin being contained at a concentration of 3 μ g/mL or more, and a stabilizing method of biotin in a liquid agent containing biotin and vitamin B2.本發明係關於一種含有生物素以及維生素B2之液劑，並且生物素經安定化之液劑，更詳細而言為含有生物素、維生素B2、以及維生素C之液劑，其中生物素濃度為3μg/mL以上，以及含有生物素以及維生素B2之液劑中的生物素的安定化方法。
