In a fluorescence observation device, a light source device generates illumination light and excitation light to be radiated onto an examination subject; a white-light image data acquisition unit generates a white-light image by capturing reflected light coming from the examination subject; a fluorescence image data acquisition unit generates a fluorescence image by capturing fluorescence generated at the examination subject; a quantification computation unit computes normalized fluorescence intensities, which are brightness values of individual pixels in the fluorescence image normalized by brightness values of corresponding pixels in the white-light image; a standard-data memory stores standard data indicating a typical correspondence relationship between the normalized fluorescence intensities and states of the examination subject; and an image-correction computation unit judges the states of the examination subject that correspond to the individual normalized fluorescence intensities on the basis of a minimum value of the normalized fluorescence intensities and the standard data.