The present invention provides a fluorescent amino acid derivative which can be synthesized by simple steps, can be excited particularly by a blue laser ray region of visible light, and has an improved light stability. These objects can be achieved by a fluorescent amino acid derivative which is an acridone derivative substituted with an amino acid to comprise an electrophilic substituent group between the amino acid and the acridone derivative. Instead of a conventional strategy that aminophenylalanine is used as a starting material to form a fluorescent group through a coupling reaction and an intramolecular cyclization reaction, a fluorescent acridone derivative is used as a starting material to furnish the material to a reactive group by a position-specific electrophilic substitution reaction, and then the acridone derivative having the reactive group is allowed to couple with an amino acid derivative.