A machining apparatus, for performing machining on a workpiece, the workpiece having a stem portion and an expanded diameter portion which is integrated with one end side of the stem portion, so as to expand its diameter larger than the stem portion, the machining apparatus comprising: a cutting device that is configured to cut the stem portion of the workpiece; a grinding device that is configured to grind the stem portion of the workpiece; and a pair of carrier members which are disposed so as to extend within a space between the cutting device and the grinding device, the pair of carrier members being configured to carry the workpiece from the cutting device to the grinding device, such that the expanded diameter portion of the workpiece can straddle the pair of carrier members, and the stem portion of the workpiece may be suspended downward from between the pair of carrier members, the machining apparatus being characterized by further comprising: a pair of pinching members which are disposed under the pair of carrier members and which are configured to pinch the stem portion of the workpiece when the workpiece is carried to a predetermined machining position on the pair of carrier members, and a deburring tool which is disposed lower than the pair of pinching members, to perform deburring with respect to the stem portion of the workpiece pinched by the pair of pinching members, wherein the deburring tool has a recess for insertion of the stem portion of the workpiece pinched by the pair of pinching members so that an opening of the recess faces the other end face of the stem portion of the workpiece, and is capable of a displacement motion in the direction of an axis of the recess while rotating around the axis of the recess, an inner circumferential surface of the recess in the deburring tool is formed so as to reduce its diameter as an inner diameter of the recess partitioned by the inner circumferential surface of the recess goes from an opening side of the recess toward an internal side of the recess, and a deburring machining section for performing deburring is provided on the inner circumferential surface of the recess. a cutting device that is configured to cut the stem portion of the workpiece; a grinding device that is configured to grind the stem portion of the workpiece; and a pair of carrier members which are disposed so as to extend within a space between the cutting device and the grinding device, the pair of carrier members being configured to carry the workpiece from the cutting device to the grinding device, such that the expanded diameter portion of the workpiece can straddle the pair of carrier members, and the stem portion of the workpiece may be suspended downward from between the pair of carrier members, the machining apparatus being characterized by further comprising: a pair of pinching members which are disposed under the pair of carrier members and which are configured to pinch the stem portion of the workpiece when the workpiece is carried to a predetermined machining position on the pair of carrier members, and a deburring tool which is disposed lower than the pair of pinching members, to perform deburring with respect to the stem portion of the workpiece pinched by the pair of pinching members, wherein the deburring tool has a recess for insertion of the stem portion of the workpiece pinched by the pair of pinching members so that an opening of the recess faces the other end face of the stem portion of the workpiece, and is capable of a displacement motion in the direction of an axis of the recess while rotating around the axis of the recess, an inner circumferential surface of the recess in the deburring tool is formed so as to reduce its diameter as an inner diameter of the recess partitioned by the inner circumferential surface of the recess goes from an opening side of the recess toward an internal side of the recess, and a deburring machining section for performing deburring is provided on the inner circumferential surface of the recess. a pair of pinching members which are disposed under the pair of carrier members and which are configured to pinch the stem portion of the workpiece when the workpiece is carried to a predetermined machining position on the pair of carrier members, and a deburring tool which is disposed lower than the pair of pinching members, to perform deburring with respect to the stem portion of the workpiece pinched by the pair of pinching members, wherein the deburring tool has a recess for insertion of the stem portion of the workpiece pinched by the pair of pinching members so that an opening of the recess faces the other end face of the stem portion of the workpiece, and is capable of a displacement motion in the direction of an axis of the recess while rotating around the axis of the recess, an inner circumferential surface of the recess in the deburring tool is formed so as to reduce its diameter as an inner diameter of the recess partitioned by the inner circumferential surface of the recess goes from an opening side of the recess toward an internal side of the recess, and a deburring machining section for performing deburring is provided on the inner circumferential surface of the recess.