In this numerical control method that drives the feed shaft of a machine tool (10) by means of a servo control unit (52), a transmission function is determined by modeling the operation of the servo control unit (52) of the feed shaft, the closed loop transmission function (G BP ) of the position loop and/or the closed loop transmission function of the velocity loop of the servo control unit (52) of the machine tool is measured using the frequency response of the feed shaft, the control subject (P P ) of the position loop and/or the control subject of the velocity loop is determined using the measured closed loop transmission function, the position loop modeling error (”P P ) and/or the velocity loop modeling error is determined from the control subject, and at least one control parameter of the servo control unit (52) is calculated using the closed loop transmission function and/or the modeling error. As a result, the optimum plurality of control parameters corresponding to the state of the feed shaft is determined easily and automatically.