A numerical control system comprises a machine tool having two axially movable sections, a tape reader for instructing a movement path of the movable section, a sampling pulse generator for generating a pulse for each predetermined time period, a position detector for detecting the amount of movement of the movable section for each sampling time, a controller for calculating an instruction position increment value corresponding to the movement for the predetermined time period of the movable section of the machine tool based on a data from the tape reader, the sampling pulse from the sampling pulse generator and a position data from the position detector, a digital-analog converter for converting a digital output of the controller to an analog value, a servo amplifier for amplifying the output of the digital-analog converter and a servo motor driven by the output of the servo amplifier. The servo motor is driven according to the instruction position increment value outputted from the controller and a workpiece is machined along an instruction movement path based on a straight line instruction, circular arc instruction, or positioning instruction.