To make machining graphics on a plane into blocks, to simplify the machining graphics, and to represent them as variables by performing desirable graphic machining by inputting and setting numeral and character for each time rectangular deformation, then forming deformation of a rectangular part of machining graphic being its set and outputting G-code conversion for its machining successively.

The front width of the external shape size of a machining rectangle on the plane is defined as a variable KW corresponding to 1st plane coordinates and the depth is defined as a variable KD corresponding to 2nd plane coordinates, and the 1st coordinate is positive in the direction to the right and negative in the direction to the left, and the 2nd coordinate is positive in the upward direction and negative in the downward direction. The G-code conversion output of one machining graphic is performed by input of the size of the rectangle and place of deformation, shape input, retraction quantity input, movement quantity input, and machining system input according to a rectangle deformation menu to enable desirable machining graphic successively to numeral variation. Consequently, the machining graphics on the plane can be made into blocks, simplified, and represented as variables.