An improved slot-drilling cutter has a tool body with plate seats at the end, which are arranged symmetrically in respect to each other. Cutting plates are arranged on the seats, whose cutting edges, as well as possibly cutting edges 41, 42, are set identically, i.e. which cover each other completely in the circumferential direction. Because of this, respectively two cutting edges are active for the drilling operation, as well as for the milling operation, which increases the metal cutting yield and allows the same advancement when drilling, as well as when milling. The slot-drilling cutter is free of lateral forces because of the symmetrical design, which permits a high degree of working precision in spite of large advancement moves.