An image forming apparatus includes an image carrier; a transferring unit; a fixing unit; a conveying unit; and a sheet shape detecting unit as defined herein, and a discharge position where the sheet is discharged from the conveying path, a feed position where the sheet is fed to the sheet conveying path and a detection position where the shape of the sheet is detected by the sheet shape detecting unit are arranged in this sequence along a sheet conveying direction to be close to one another, immediately downstream in the sheet conveying direction from a fixing position where the toner image is fixed to the sheet.