To prevent adverse effect, on machining accuracy, of cogging thrust of linear motors when used in a combined linear motor driving a machine tool. Three linear motor movers are fixedly attached to a moving table of a machine tool, while three linear motor stators are fixedly attached to a base. The three linear motors are driven in parallel to thereby drive the moving table. The respective linear motor stators are fixed to the base so as to have fixed phases relative to the base, stepwisely displaced by an electrical angle 60° whereby cogging thrust is leveled in the entire combined linear motor.