The number of ACF can be easily counted without overlooking the presence thereof and the observation time can be shortened. Disclosed is a fluorescence observation device (1) provided with a light source unit (40) put into a body cavity of an organism and adapted for illuminating the inner wall of the body cavity with an excitation light beam, an image capturing unit (20) for capturing an image of the fluorescence emitted when GST-p sensitive fluorescent probe having sensitivity to GST-p produced in the inner wall of the body cavity in response to the excitation light beam emitted from the light source unit (40) is excited and acquiring image information, a position control unit (30) for moving the light source unit (40) and the image capturing unit (20) with respect to the inner wall of the body cavity, and a counting unit (72) for counting the number of regions where fluorescence is emitted and which is shown in an image acquired by the imaging unit (20).
FLUORESCENCE OBSERVATION DEVICE