An image forming apparatus for inputting an original image and forming an image on a recording medium, includes an image direction detection unit for detecting the image direction of an original image, and a control unit for controlling image forming device to perform predetermined image forming processing in accordance with the detection result of the image direction detection unit. The image direction detection unit outputs a degree of determination as the detection result of the image direction, and a level for determining whether or not the predetermined image processing is done is set for the degree of determination.