The invention discloses a mechanical cutter for leather processing. The mechanical cutter comprises a leather cutter box body, a first slide block is arranged at the top of the leather cutter box body, and a first leather cutter body and a second leather cutter body are arranged at one side of the leather cutter box body; the second leather cutter body is movably connected with the first leather cutter body through a second screw, a first leather cutter opening is formed in the surface of the first leather cutter body, and the first leather cutter body is fixedly connected with a first slide block opening through a first screw. According to the mechanical cutter for leather processing, by arranging the first leather cutter body and the second leather cutter body, the first leather cutter body can cut a leather face by using a cutter face so that the leather can be cut into multiple small leather blocks, and in cooperation with the first leather cutter body and the second leather cuterbody, the leather can be cut so that the leather can be cut into different arc shapes; an arranged leather mold block is provided with a fixed pattern, the pattern can be stamped on the surface of theleather, and the usability of the leather is improved.