PURPOSE: To replace no cam, in the case of changing the work shape of a work, despite of an automatic lathe intaking a cam type.

CONSTITUTION: The radius of cams 20, 30 are made in the length according to an angle θ. The moving position of a tool is thus apart from the rotation angle of the cam 20, 30. An NC device 5 drives a servomotor 4, controlling the rotation of the cam 20, 30 in the reciprocal direction, and moving a tool 8, 11 as per being programmed in advance. Consequently, there is no need for replacing the cam 20, 30, even in the case of changing the work shape of a work.