PURPOSE: To improve the extent of productivity in multikind and small production by detecting a work form at a work carry-in route, discriminating the type, and selecting a machining program conformed to the work type.

CONSTITUTION: This automatic lathe is provided with a work delivery device 17 setting a work W to the spindle 2. Also, there is provided with a work type discriminating means 18 which detects a work form at a carry-in route of the work delivery device 17 and discriminates each type of the work W. Accordingly, this discriminating means 18 detects the form of each work W taken in successively at the carry-in route of the work delivery device 17, thereby discriminating the type of the work W. According to the discriminated result, a program selecting means 23 selects each of machining programs 25, 26 conformed to the work type. Thus, the work W is machined by these selected machining programs 25, 26.