A fluorescence detecting system includes a stimulating light projector which projects onto an object part which has been dosed with a fluorescence agent first stimulating light in the exciting wavelength range of the fluorescence agent and second stimulating light which differs from the first stimulating light in the wavelength band and is in the exciting wavelength range of the auto-fluorescence material contained in the object part, and a fluorescence information obtainer which obtains the fluorescence from the fluorescence agent information based on the fluorescence from the fluorescence agent emitted from the object part in response to projection of the first stimulating light and the auto-fluorescence information based on the auto-fluorescence emitted from the object part in response to projection of the second stimulating light. The fluorescence agent is a fluorescence agent which does not emit fluorescence in response to projection of the second stimulating light.