A cutting tool (35) for machining a differential case, the cutting tool (35) being attached to a machining apparatus and used to perform cutting on a spherical inner surface of a differential case (10), the cutting tool (35) including: a shaft part (50); a cutting edge (51) laterally protruding from the shaft part (50); a fixing part (53) formed at one end side of the shaft part (50) and that is for fixing the shaft part (50) to the machining apparatus; and a retaining part (54)formed at the other end side of the shaft part (50) and that is for retaining the shaft part (50) by the machining apparatus, wherein the cutting tool (35) is able to perform cutting on the spherical inner surface of the rotating differential case (10) in a both-ends-held state in which both the fixing part (53) and the retaining part (54) are supported by the machining apparatus.
展开▼