Notching device used for cylindrical piece

The utility model relates to a notching device used for a cylindrical piece, and belongs to the field of punching. The notching device comprises a lower die plate, a die pedestal, a cushion block, a female die shaft, a female die, a snap ring, an upper die and an upper die plate. The female die shaft is connected with the female die in a lap joint mode to form a positioning section with the outer diameter matched with that of a workpiece. The left end of the female die shaft is supported through the die pedestal. The right end of the female die shaft is supported through a cushion block. The snap ring clamps the workpiece and conducts rotating notching. The notching device is simple in structure and convenient to machine, machining accuracy of notching in the circumferential direction is high, production efficiency is improved, and the problem that a part deforms when the diameter is reduced after the whole female die is reground is solved; the problem that interference with the part occurs when waste falls in the notching process is solved.