A sheet processing apparatus includes a sheet stacking unit, a binding unit, a folding unit, a conveyance unit, a press unit, a grasping unit, and a control unit. The binding unit performs binding processing on a sheet bundle stacked in the sheet stacking unit. The conveyance unit conveys a sheet bundle folded by the folding unit. The press unit presses a fold line portion of the conveyed sheet bundle from a direction perpendicular to a surface of a front page of the sheet bundle while moving along the fold line portion. The grasping unit is switched between a first state in which the grasping unit fixes the sheet bundle in position and a second state in which the grasping unit does not grasp the conveyed sheet bundle. The control unit shifts the grasping unit to the first state and causes the press unit to press the sheet bundle.