An image forming apparatus starts to change a curl correcting amount until when an upstream end in a sheet conveying direction of a preceding sheet passes through a curl correcting unit and finishes changing the curl correcting amount until when a succeeding sheet that follows the preceding sheet reaches the curl correcting unit in a case when the preceding sheet and the succeeding sheet are both guided in the curl correcting unit through a conveying path and when the curl correcting amount is changed between curl correcting amounts of the preceding sheet and the succeeding sheet.