Abstract: The machine tool structure of the invention is : saddle which can slide toward X axle direction set at the machine table; bed which can slide toward Y axle direction set at the saddle; door type machine pole which includes vertical and horizontal poles set at the bed; a machine head which can load cutting main shaft and can only move toward Z axle direction but not Y axle direction at horizontal pole set at the horizontal pole; the center of the lead screw leaning into one side near machine pole of the plane surface which is created by the sliding rail between the machine head and machine pole; this causes the gravity center of the machine head moving toward the machine pole.