It is an object to provide an image processing apparatus which can obtain an image reproduction that accurately corresponds to an original color when an ordinary color original is read and which can obtain an accurate marker edition result when a marker original is read. When a color scanning mode to read the color image is selected, an original ground removal by a prescan is not performed. When a marker edition scanning mode to read the marker original is selected, the original ground removal is executed. Thus, a color reproduction which accurately corresponds to the original is executed in the color scanning mode. In the marker edition scanning mode, the color recognition of the marker color is accurately performed without being influenced by the ground color.