In orter to establish methods of potato processing for mixed cooking with rice as main diet, fundamental research was carried out. On the basis of the previous experiments about potato granules, the yield of products, the process of manufacture, and its economics we re determined The results are the following. 1. Yield of products are; ① 22.2% under dipping treatment in K₂S₂O_5 solution. ② 21.7% under dipping treatment in HCl solution. ③ 20.5% under blanching treatment in boiling water. ④ 19.9% under dipping treatment in boiling K₂S₂O_5 solution. ⑤ 18.75 under dipping treatment in boiling HCl solution. 2. The processing of potatoes is as follows raw materials→peeling→cutting→treatment for polyphenol oxidase inactivation→drying→products 3. Potato granules are ordinarily not commercial when compared with rice, however, there are times when it is. When rested land is planted with potatoes a high yield is produced. This will lower the price of the potato and make it commercial compared with rice.