clearly seeing through the observation window 4 the specimen a and the examination head 6 which are brightly illuminated with the visible light l 3 with the third spectral band b 3 emitted from the illumination light source 3 consequently unlike with the known method blind adjustment in a darkroom is not required according to this embodiment and hence an annoying repeated procedure of turning on and off the illuminating light in the darkroom can be avoided in the dark box apparatus for fluoroscopy 1 according to this embodiment the baffle plate 26 provided in the dark box main body 2 prevents the visible light l 3 emitted from the illumination light source 3 from directly reaching the observation window 4 therefore the observer is prevented from looking directly at the illumination light source 3 because of this the observer is not too dazzled to see the interior of the dark box main body 2 which would occur if the observer looked directly at the illumination light source 3 furthermore according to this embodiment the optical unit 9 including the excitation light source 11 is arranged outside the dark box main body 2 for this reason the temperature in the dark box main body 2 is prevented from rising due to heat emission of the excitation light source 11 this is advantageous in preventing the specimen a from becoming dry and maintaining stable examination conditions although this embodiment has been described by way of the third spectral band b 3 which is shorter than the first spectral band b 1 of the excitation light l 1 and the second spectral band of the fluorescence l 2 alternatively a spectral band b 3 u2032 that is.