The invention relates to a diagnostic device and particularly discloses a diagnostic device for scanning the irises of eyes. The diagnostic device comprises a mainframe, a hand-held reader and a display; the diagnostic device is provided with a demountable lens, an above-1.3 megapixel CCD (charge-coupled device), an LED lamp and a storage module which can conveniently shoot sharp images; the shotimages can be saved as the computer general image formats, such as JPG, BMP and the like; and then, the results can be automatically analyzed by the computer image comparison technology, particularly, pits, gaps, color spots, lines, density and color variation can be judged from the iris images to obtain the diagnosis result reflecting the change in health conditions. The automatic iris diagnostic device has the advantages that the application is convenient, the collected iris images are sharp, the information is accurate and all-around, the structure is simple, the cost is low, the images can be saved and amplified, and the results can be easily analyzed and judged.