A method of automatically measuring the flexure value of a wire electrode 1 in a wire-cut electric discharge machine, such that at a measurement point in the course of electric discharge machining, the electric discharge is temporarily stopped, and whether or not a wire electrode 1 and a workpiece 2 come into contact is sensed by a contact sensing device 107a. The wire electrode 1 and the workpiece 2 are moved relatively to advance or retreat in accordance with a sensed touch signal TS, and a distance .epsilon..sub.1 of movement until the contact state changes is measured. The flexure value .epsilon. is calculated from the measured movement distance .epsilon..sub.1 and the size of the discharge gap.