An oral cavity endoscope diagnosis supporting device comprises at least two sets of monochromatic source generators, an image sensor, a storage unit and a data processing unit. Each set of the monochromatic source generators emit one of seven visible lights, the monochromatic lights emitted by the monochromatic source generators are different from one another, and all sets of the monochromatic source generators are used for emitting the monochromatic lights to irradiate user teeth to stimulate fluorescence spectra; the image sensor can be used for recording image information III of the fluorescence spectra, obtained through stimulation of the monochromatic lights emitted by the monochromatic source generators, of the user teeth; the storage unit stores a comparison chart of image information IV of the fluorescence spectra, obtained through stimulation under irradiation of the monochromatic lights, of the abnormal teeth; the data processing unit is used for comparing fluorescence spectrum images recorded by the image sensor with fluorescence spectrum images in the comparison chart.