A sheet processing apparatus including a first conveying member that conveys a sheet, a second conveying member that receives the sheet conveyed by the first conveying member and further conveys the sheet to a subsequent stage, a third conveying member that receives the sheet conveyed by the first conveying member and further folds the sheet, a guiding member that guides the sheet when the sheet is folded by the third conveying member, and is arranged between the second conveying member and the third conveying member. The sheet is guided along the guiding member when a bending part of the sheet is conveyed to the third conveying member by rotating the second conveying member in a reverse direction while the sheet is held by the first conveying member and the second conveying member.