Stepped drill bit

The utility model belongs to the technical field of machining workpieces, and particularly relates to a stepped drill bit. The utility model relates to a ligament cutter which comprises a cutter body,the cutter body is provided with an original chipping containing groove, a first diameter step, a second diameter step and a third diameter step which are spirally arranged in the axial direction ofthe cutter body, first ligaments are arranged on the second diameter step and the third diameter step, the first ligaments extend to the bottom of the original chipping containing groove, and second ligaments are arranged on the third diameter step. The second ligament also extends to the bottom of the original scrap containing groove, and meanwhile a new scrap containing groove is formed betweenthe first ligament and the second ligament; the cutter groove and the ligament at the step position are improved, the service life of the drill bit is prolonged, the phenomenon that a cutter is scrapped due to the fact that the