To provide a metal mold which is accurate and in which various curves are incorporated by forming the metal mold using machining work applied to a metal mold material provided in a precision working machine and forming profiling lines in the metal mold by blanking cutting, and rupture based on numerical curve data.

A profile drawing selection means 3 gives an instruction for the selection of curve data stored in the storing device 6 of a computer 2 to the storing device 6 through a program retrieval, means 4 and a program decision means 5. Also the decided curve data IS transmitted from the storing device 6 to which the instruction is given and displayed on a drawing display means 8 through a program read means 7, and its evaluation is displayed on the display part. Therefore it can be confirmed whether the specified curve data is accepted or rejected. When the displayed data is accepted, a curve software data is transmitted to a wire cut control part 11 through a working control means 10, and electric discharge machining is started based on the curve software data.