Outside air shut-off container

Patent Pending Because an O-ring of synthetic resin is pyrolyzed in the atmosphere at a high temperature of 150 DEG C or more, the airtightness cannot be maintained. In an outside air shut-off container according to the present invention, an inert gas is supplied between an O-ring, which hermetically seals a process chamber and a cover member, and the outside air while a gas passage formed between the O-ring and the outside air is covered with a sealing cover. Additionally, an aluminum oxide layer is formed on a contact surface of the O-ring to increase the pyrolysis temperature of the O-ring.