To provide a fluorescent endoscope system performing the good observation of fluorescence by reducing the effect due to auto-fluorescence, a fluorescence observation device, a fluorescence observation method, a fluorescence data processor and a fluorescence data processing method.

A light source unit 4 and a light guide 7 are provided as an exciting light irradiation part for irradiating an observation target A in the state that a fluorescent coloring matter is not attached or absorbed with exciting light of which the wavelength contained in the absorption spectrum band of the fluorescent coloring matter attached to or absorbed by the observation target A in the body cavity. As a compensation data acquiring part for acquiring compensation data compensating the effect of the auto-fluorescence of the observation target A contained in the observation result when the fluorescence from the fluorescent coloring matter attached to or absorbed by the observation target A caused by the irradiation with exciting light is observed by utilizing the observation result of the observation target A at the time of the irradiation with the exciting light by the exciting light irradiation part, an imaging element 14, an imaging element drive circuit 15, a variable spectroscopic element control circuit 16 and a third frame memory 17c are provided.