To provide an enlarging observation device capable of easily measuring the size of an observation object on the display screen of a picture display device.

This device has a microscope lens barrel 7 as an optically enlarging means which obtains the optically enlarged picture of the observation object with instructed enlarging magnification, an image pickup device 8 as an image pickup means picking up the optically enlarged image, the picture display device 51 displaying the image pickup data of the object to be observed on the screen, and an enlargement magnification detecting part 35, a scale producing part 36, and a picture display part 34 as a scale display means displaying scale for specifying the real size of the object to be observed on the screen of the device 51 in accordance with the enlarging magnification.