The present invention relates to a method of analyzing a polyamine having a plurality of amino groups in the same molecule or a monoamine having an amino group and a phenolic hydroxyl group in the same molecule on the basis of the measurement result of the intensity of excimer fluorescence emitted as a result of the derivatization of the polyamine or the monoamine with a fluorescence derivatization reagent having a pyrene group. The method is characterized in that the fluorescence derivatization reagent comprises 2-chloro-4-methoxy-6-(4-(pyren-1-yl) butoxy)-1, 3, 5-triazine represented by the formula (2).