A sheet processing apparatus includes a pressing unit and a shifting unit. The pressing unit has a protrusion and presses the protrusion against a fold section of a sheet. The fold section extends in one direction. The shifting unit moves at least one of the protrusion of the pressing unit and the sheet so as to shift a pressing position, at which the fold section is pressed by the protrusion, in the one direction or in a direction opposite to the one direction.
