The invention relates to a chamfering tool. The chamfering tool comprises a tool bit, wherein the tool bit comprises a chamfering cutting edge. The chamfering tool further comprises a positioning piece which is used for being in positioning fit with a center hole or the outer circumferential face of a part to be machined, the upper end of the positioning piece is a first positioning part which iscoaxially arranged with the rotation axis of the tool bit, the lower end of the positioning piece is a second positioning part used for being in coaxial positioning fit with the center hole or the outer circumferential face of the part to be machined, and the first positioning part and the second positioning part are coaxially arranged. According to the chamfering tool, it is guaranteed that the rotation axis of the tool bit is coaxial with the axis of the part to be machined through the positioning piece, so that a machined chamfer is uniform in size, and the problem that in the chamfering process, chamfering fails due to the fact that the rotation axis of the tool bit is inclined is solved.