To provide an NC knurling lathe capable of knurling processing by a cutting tool.

An NC knurling lathe 10 comprises: a spindle head 2 arranged on a bed 1 and rotatably supporting a main spindle 2a; a main spindle motor 2e for driving the main spindle 2a; a main spindle control device 9a for controlling the main spindle motor 2e and a cutting tool moving device 11 arranged on the bed 1 and movably supporting the cutting tool 8b. The NC knurling lathe 10 applies the knurling processing by moving the cutting tool 8b while rotating the main spindle 2a. The cutting tool moving device 11 comprises: a Z axis movement device 6 for moving the cutting tool 8b in a Z axis direction, an X axis movement device 4 for moving the cutting tool 8b in a X axis direction and a movement control device 9b for controlling operation of the Z axis movement device 6 and the X axis movement device 4, and comprises: a synchronous control device 9 for synchronously moving the cutting tool 8b in the Z axis direction at a predetermined moving distance by the movement control device 9b while rotating the main spindle 2a at a predetermined rotation angle by the main spindle control device 9a.