An image forming apparatus which can prevent deformation of a sheet due to heat generated at a fixing section as much as possible, and can reduce the amount of waste paper even when the sheet is partially deformed, in which: an upper fixing section and a lower fixing section form a fixing nip for conveying a continuous sheet in a tightly sandwiching manner in a state where the upper fixing section and the lower fixing section are in pressure contact with each other; the upper fixing section and the lower fixing section are separated from each other when image formation is not performed; and a detection section detects deformation of the continuous sheet at a closest part between the upper fixing section and the lower fixing section.