Oxygen partial pressure control device and the gas supply method

Without missing a gas having a controlled oxygen partial pressure (the purified gas), and can be supplied to other devices the sample preparation chamber, etc., in the other device, working with purified gas (sample preparation work) efficiently to provide a oxygen partial pressure control device and the gas supply method capable of performing. It comprises a gas purification unit 21 for purifying the oxygen partial controls the pressure gas in the range of 0.2 to 10 Supplying the purified gas in the tank 20 to another device. Comprising a circulation circuit 19 comprising a tank 20 and a gas purification unit 21. And a gas filled in the tank 20 is circulated to the circulation circuit 19, store the purified gas to be purified by a gas purification unit 21 to the tank 20.