To provide a method of manufacturing that can reduce dimensional accuracy required for an arm and a chuck that constitute a substrate holding mechanism while the accuracy of the substrate-holding position is easily enhanced.

A hole 20, which be the center of the substrate-holding position, is formed in the arm 6 while a positioning pin 22 and a positioning circular disc 24 which is slightly larger than the substrate are prepared. The circular disc 24 has a hole at its center. The positioning pin 22 is engaged in the hole 20 of the arm and also in the hole of the positioning circular disc 24. While circular arc walls 14 of a pair of chucks 10 are fitted to the side face of the positioning circular disc 24, both chucks 10 are fixed to the arm. Subsequently, the positioning pin 22 and the positioning disc 24 are removed.