A wire electric discharge machine comprising: a NC device; a tensile force generating unit for giving a tensile force to a wire electrode; and a tensile force detector for detecting a tensile force of the wire electrode, in which a detected tensile force detected by the tensile force detector is fed back to perform feedback control of the tensile force of the wire electrode such that the tensile force becomes equal to a set tensile force, characterised in that the wire electric discharge machine further includes a calibrating unit which carries out calibration for obtaining a detected deviation amount of the tensile force detector based on the set tensile force and a tensile force detected by the tensile force detector when the set tensile force is applied, the calibrating unit correcting output of the tensile force detector by the detected deviation amount which is obtained by the calibration, and the wire electric discharge machine has a function to correct a detected value of a tensile force for carrying out feedback control of the tensile force of the wire electrode based on a corrected detected tensile force which is obtained by correcting the detected tensile force of the tensile force detector by the calibrating unit, wherein in the calibration of the calibrating unit, the detected deviation amount is obtained and stored as a function of the set tensile force, and when electric discharge machining is carried out, the calibrating unit obtains a detected deviation amount with respect to a value of the tensile force to be set by the function, and the detected tensile force detected by the tensile force detector is corrected with the detected deviation amount, as a corrected detected tensile force. a NC device; a tensile force generating unit for giving a tensile force to a wire electrode; and a tensile force detector for detecting a tensile force of the wire electrode, in which a detected tensile force detected by the tensile force detector is fed back to perform feedback control of the tensile force of the wire electrode such that the tensile force becomes equal to a set tensile force, characterised in that the wire electric discharge machine further includes a calibrating unit which carries out calibration for obtaining a detected deviation amount of the tensile force detector based on the set tensile force and a tensile force detected by the tensile force detector when the set tensile force is applied, the calibrating unit correcting output of the tensile force detector by the detected deviation amount which is obtained by the calibration, and the wire electric discharge machine has a function to correct a detected value of a tensile force for carrying out feedback control of the tensile force of the wire electrode based on a corrected detected tensile force which is obtained by correcting the detected tensile force of the tensile force detector by the calibrating unit, wherein in the calibration of the calibrating unit, the detected deviation amount is obtained and stored as a function of the set tensile force, and when electric discharge machining is carried out, the calibrating unit obtains a detected deviation amount with respect to a value of the tensile force to be set by the function, and the detected tensile force detected by the tensile force detector is corrected with the detected deviation amount, as a corrected detected tensile force.