A sheet finisher of the invention includes a saddle stitch unit configured to stitch a center of a sheet bundle in which printed sheets are bundled, a fold unit configured to fold the center stitched by the saddle stitch unit and to form a fold line, and a fold reinforcing unit configured to reinforce the fold line formed by the fold unit, the fold reinforcing unit includes a placement table on which the sheet bundle transported from the fold unit is placed, and a roller unit that includes a reinforce roller and moves the reinforce roller along a direction of the fold line while pressing it to the fold line, and the placement table is provided with a groove-like edge clearance along an edge of the sheet bundle.