The invention concerns a device for trim patterning furs with a group of knife blades, arranged at equal intervals next to each other and aligned parallel to each other, whose cuts run acute-angled to the leather back side of the material surface, with a convex slot plate opposite the material surface displaying a pass-through slot for each knife blade, and with an adjustment arrangement for establishing a desired projecting length for the knife blades above the convex side of the slot plate.