The invention relates to a graded cutting device. The graded cutting device comprises an outer housing 1, a positive displacement motor 2, a shaft coupling 3 and a transmission shaft 4, and the positive displacement motor 2, the shaft coupling 3 and the transmission shaft 4 are arranged in the outer housing 1. The upper part of the transmission shaft 4 is provided with a by-pass port 5, the lower part of the transmission shaft 4 is provided with a first-grade joint 13, the lower part of the outer housing 1 extends to form a diameter-expanded stabilizer 10, the stabilizer 10 is provided with several driven gear cavities which are distributed uniformly in the circumferential direction from bottom to top in the axial direction, the interior of each driven gear cavity is provided with a driven gear 8, each driven gear 8 and the transmission shaft 4 are coaxial, the lower end of each driven gear 8 is provided with a second-grade joint 9, the exterior of the transmission shaft 4 is fixedly connected with a driving gear 7, and the driving gear 7 is in engaged rotating cooperation with the driven gears 8 which are distributed uniformly peripherally. Compared with a conventional rock breaking tool, the graded cutting device is advantaged in that under the condition of the same energy consumption and the same drilling period, more rocks can be cut, the drilling speed is faster, and the rock breaking efficiency is higher; and the graded cutting device is characterized by being simple in structural design, reliable in performance, convenient to operate and the like.