A processor included in the image processing device acquires a medical image, outputs observation target identification information indicating an observation support target part or indicating that the medical image is out of an observation support target by inputting the medical image to an observation target identification algorithm, selects, from a plurality of observation support algorithms, one specific observation support algorithm based on the observation target identification information, outputs observation support information by inputting the medical image to the specific observation support algorithm, and performs a control of notifying of the observation support information.