A sheet processing apparatus includes a conveying portion for conveying sheets, a conveying path for sheets, a stack portion for stacking sheets, a first binding portion having a first binding member and moving in a crossing direction crossing to the conveying direction, a first regulating portion which regulates a position of a sheet bundle stacked on the stack portion, a second regulating portion which regulates a position of a sheet bundle stacked on the stack portion, a third regulating portion which regulates a position of a sheet bundle, and a second binding portion which has a second binding member and binds a corner portion of a sheet bundle without a staple. The first binding portion binds a corner portion of a sheet bundle by a staple. The second binding member is located at a downstream of the first binding member in the conveying direction.