To provide a medical display device which manages photography using only one photographing means and is incorporated appropriately into an operating microscope or the like.

The medical display device takes photographs of a bright field (visible light) and a dark field (fluorescence) of a visual field using only one CCD camera 13. A dark field image is processed by chromakey to extract only a fluorescence image (an affected area), and the fluorescence image is superimposed and displayed on a bright field image. Because the bright field and the dark field are the same visual field, the fluorescence image of the dark field matches with the affected area in the bright field image. By displaying the fluorescent affected area on the bright field image in real time, the device is used not only for observation but also for an operation using an operation microscope 1 by incorporating the device into the microscope. Because the device uses only one CCD camera 13, the device can be incorporated into the operating microscope 1 easily.