An image processing apparatus that can easily change the categories of the main object, comprises, an object detection unit for detecting an object categorized as one of at least two categories from an image, a setting unit for setting a first category as a priority category on an object having a predetermined priority among one of the objects detected by the object detection unit; and a region designation unit for designating a predetermined region on an object on a display screen, wherein the setting unit can change the priority category from the first category to a second category different from the first category when the predetermined region of the object designated by the region designation unit is the second category.