An image processing apparatus includes a computer, a memory, and a program stored in the memory that, when executed by the computer, causes the computer to perform acquiring an image obtained by capturing a parking lot including a plurality of parking regions capable of parking a plurality of automobiles, deciding, for the image, a determination target region for each of the plurality of parking regions so as to exclude a shielded region that is shielded by an automobile in a case in which the automobile is parked in another parking region, and detecting, from the image, an automobile in each determination target region, and determining, based on a result of the detection, the presence/absence of parking of an automobile in each of the plurality of parking regions.