A dental caries detecting system 1 according to the invention includes an ultraviolet irradiation device 2, a fluorescence receiving device 3 that receives fluorescence from a tooth based on ultraviolet irradiation from the ultraviolet irradiation device 2, a fluorescence data analysis portion 4 that analyzes fluorescence data transmitted from the fluorescence receiving device 3, and a display 5 that displays analysis data analyzed by the fluorescence data analysis portion 4. The fluorescence data analysis portion 4 is adapted to analyze said fluorescence data based on the fluorescence intensities in at least two wavelength bands in a visible light range.