A medical system has a treatment device having a reference-position designation portion, an endoscope acquiring a plurality of captured images, a storage device, a controller generating a plurality of display images corresponding to the captured images, and a display. The controller determines an arbitrary position in the display image as a reference position, detects a region in the display image where the treatment device is displayed as an excluded region and selects a reference image from a region in the display image excluding the excluded region, records the reference image in the storage device, calculates a relative position from the reference position to the reference image, detects the reference image from the plurality of display images after the reference image is generated, recognizes the reference position in the display image, and controls an operation of the endoscope to make the reference position to be coincided with a target position.
