The concentration distribution of a fluorescence dye capable of selectively staining normal tissue and abnormal tissue is accurately observed by eliminating the unevenness due to irregular distance from the distal end of an endoscope to an organism surface or the surface roughness of the organism. There is provided a fluorescence observation device for organism tissue comprising: an excitation light optical system for irradiating an organism tissue adhered or infiltrated with a first fluorescence dye whose stainability is different between normal tissue and abnormal tissue in the organism tissue, and a second fluorescence dye whose fluorescence wavelength or absorption wavelength is different from that of the first fluorescence dye and whose stainability is nonselective between normal tissue and abnormal tissue in the organism tissue, with excitation light which excites the first fluorescence dye and the second fluorescence dye, either simultaneously or in a time sharing manner a fluorescence detecting section for separately detecting fluorescence from the first fluorescence dye and fluorescence from the second fluorescence dye excited by the excitation light from the excitation light optical system a compensation processing section for compensating the fluorescence information from the first fluorescence dye, based on the fluorescence information from the second fluorescence dye detected by the fluorescence detecting section and a display section for displaying the fluorescence information compensated by the compensation processing section.
