1. A fluoroscopy apparatus comprising: an illumination portion having a light source that radiates illumination light and excitation light onto a subject; a fluorescence-imaging unit that acquires a fluorescence image by imaging fluorescence generated at the subject by the radiation of the excitation light from the illumination portion; a return-light imaging unit that acquires a reference image by imaging return light returning from the subject by the radiation of the illumination light from the illumination portion; and an image-correction unit that corrects the fluorescence image acquired by the fluorescence-imaging unit by using the reference image acquired by the return-light imaging unit, wherein the image-correction unit obtains a correction reference image by raising a luminance value of the reference image to the power of a correction factor that is obtained such that ratios of a luminance of the fluorescence image to a luminance of the reference image, in which the luminance value of the reference image has been raised to the power of the correction factor, match each other at a plurality of different distances, and obtains a corrected fluorescence image by dividing the fluorescence image by the correction reference image.