The distribution of abnormal tissue, such as lesions, in an observed object is precisely detected regardless of the distribution of absorbing material present in a living organism. Provided is a fluorescence imaging apparatus (1) including an excitation-light radiating unit (2) that irradiates an observed object with excitation light of a plurality of wavelengths a filter (14) that transmits fluorescence in a specific wavelength band from among fluorescence produced by the observed object in response to the excitation light radiated from the excitation-light radiating unit (2) a light detector (15) that detects the fluorescence transmitted through the filter (14) and a computing unit (18) that calculates a fluorescence intensity ratio in the same wavelength band in response to the excitation light of the plurality of wavelengths, which is detected by the light detector (15).
