PROBLEM TO BE SOLVED: To provide a high pressure space forming apparatus for accommodating a person (a human body) or a small animal in an internal space adjusted to a set air pressure exceeding atmospheric pressure to take oxygen into the body.SOLUTION: The high pressure space forming apparatus X includes an air adjusting hole 35 exhausting high pressure air to the outside of a pressure box 31 to adjust the internal space to the set air pressure an air vent window 33 exhausting high pressure air to the outside of the pressure box 31 to adjust the internal space to atmospheric pressure and an air vent window body 34 arranged in the internal space to close or open the air vent window 33 from the inside. The air vent window body 34 is arranged to close the air vent window before the supply of high pressure air by a high pressure air supply means 6. The air vent window body 34 air-tightly closes the air vent window 33 upon receiving the opening/closing air pressure exceeding the atmospheric pressure and lower than the set air pressure with the supply of high pressure air, and is separated from the air vent window 33 by the weight of the air vent window body 34 to open the air vent window 33 when the internal space reaches the opening/closing air pressure from the set air pressure in association with the supply stop of high pressure air by the high pressure air supply means.COPYRIGHT: (C)2012,JPO&INPIT【課題】大気圧を超える設定気圧にされる内部空間に人間(人体)や小動物を収容して、体内に酸素を取り込むための高圧空間形成装置。【解決手段】高圧空気を耐圧ボックス31外側に排気して内部空間を設定気圧に調整する空気調整穴35と、高圧空気を耐圧ボックス31外側に排気して内部空間を大気圧にする空気抜き窓口33と、内部空間に配置され空気抜き窓口33を内側から閉鎖又は開放する空気抜き窓体34と、を備え、空気抜き窓体34は高圧空気供給手段6による高圧空気の供給前に空気抜き窓口を閉じるように配置され、高圧空気の供給に伴って大気圧を超えて設定気圧未満の開閉気圧を受けると、空気抜き窓口33を気密に閉鎖するとともに、高圧空気供給手段による高圧空気の供給停止に伴って内部空間が設定気圧から開閉気圧に達すると、空気抜き窓体34の重量によって空気抜き窓口33から離間して、空気抜き窓口33を開放する高圧空間形成装置X。【選択図】図1