To provide a cutting machine accurately detecting the amount of displacement of the tailstock spindle relative to the chuck, and also to provide a method of correcting the working position of the cutting machine.

The movement amount (Geometric-Offset value) of a cutter moved from the origin of a NC table toward the axis of a test material 66 and an inclination angle θ (namely, the virtual data on the virtual moving path of a tip 26A relative to a long workpiece) are set in X- and Z-directions. Namely, based on the virtual data on the virtual moving path of the cutter 26, a CPU corrects the inclination θ of the chuck 12 and the axis of the tailstock spindle 89 and the inclination of an unshown NC slider for working the long workpiece. Specifically, the CPU corrects the cutter 26, based on the virtual data on the virtual moving path for working the long workpiece. Since the virtual data on the virtual moving path of the cutter 26 is accurately detected, the machining accuracy is increased even when the long workpiece is machined.