Abstract: The present invention provides an image forming apparatus including an image forming unit configured to form an image on a sheet, a conveying path along which the sheet is conveyed to the image forming unit, a sensor configured to detect the width of the sheet in a direction perpendicular to a conveying direction, and a control unit configured to determine a conveying state of the sheet in the direction perpendicular to the conveying direction according to an output of the sensor, and configured to control a conveyance interval of the sheet according to the determination result. The control unit sets the conveyance interval according to the width of the specified sheet and the width detectable by the sensor, regardless of the determination result.