When jam occurs in one of a tandem conveyance path and bypass conveyance path, a sheet is automatically discharged from the conveyance path where no jam has occurred. A sheet retained at the upstream side with respect to a first fixing device in a sheet conveying direction is automatically discharged to the outside of an image forming apparatus by using the conveyance path where no jam has occurred. After the automatic discharging of the sheet is completed, a user is prompted to remove the jammed sheet.