An endoscope system capable of easily measuring a size of a subject is provided. In the endoscope system, since an index figure indicating an actual size of a specific region of a test object is displayed together with an image of the subject, a user can measure the specific region easily by comparing the specific region with a marker. Since the size of the index figure is set in accordance with a spot position, there is no need for distance measurement, a device configuration is simple, and measurement can be quickly and easily performed. In addition, a specific value of the “actual size” can be set in accordance with conditions, such as the type of test object and the purposes of measurement. Additionally, an affected region can be the specific region in a case where the test object is a living body.