A first folding portion includes: a first folding roller pair consisting of a common roller and a first roller; and a blade member that feeds a sheet to a first nip, thereby forming a first fold on the sheet in the first nip. A second folding portion includes a second folding roller pair consisting of the common roller and a second roller, thereby forming a second fold on the sheet in a second nip. The common roller and the first roller are parallel in a conveying direction in a case where the sheet is guided toward the first folding portion. The blade member moves in a direction that is substantially orthogonal to a conveyance surface. The common roller is disposed on an upstream side of the first roller in the sheet conveying direction.