Abstract: Disclosed is a fluorescent labeling agent containing quantum dots, which exhibits little fluctuation in luminous properties in accordance with the environment where the fluorescent labeling agent is stored and therefore has high environmental stability, and which has high luminous intensity. Specifically disclosed is a fluorescent labeling agent containing quantum dots, which comprises: (1) a fluorescent labeling agent core part which comprises at least three quantum dots per a fluorescent labeling agent and a protective material; and (2) an organic surface-coating layer which coats the fluorescent labeling agent core part, wherein the fluorescent labeling agent core part has an average particle diameter of 10 to 50 nm.