An electrical discharge machining apparatus includes a simulator. The method uses a mixed carrier gas of hydrogen gas and nitrogen gas to control formation of a facet group including at least the 33-62 facet by the regrowth, and conducting the regrowth until a plane parallel to the surface of the first III-V Group compound semiconductor layer is once annihilated, thereby fabricating a III-V Group compound semiconductor having low dislocation density. Gates of the transistors have predetermined voltages applied to them. The present thus invention defines an \u201cOperating System Guard.