A manufacture method of a light emitting device is provided. In order that the fluctuations in the dynamic pressure and the grinding resistance between respective grinding wheels and workpiece portions ground therewith do not grow as a combined or synergy effect, the inclined grooves on each grinding wheel are shifted in angular phase from those on another grinding wheel, so that grinding efficiency and accuracy can be enhanced. In some embodiments the amount of memory accessible to the CPU is decreased or increased, in other embodiments the power setting applied to portions of memory is decreased or increased.