A gas pressure device comprises a flexible accommodating chamber (100) and a housing (200) sleeved outside the flexible accommodating chamber (100). The housing (200) comprises a body (210) and clamping rings (220) disposed at two ends of the body (210). The flexible accommodating chamber (100) is fixed in the housing (200) by means of the clamping rings (220), and a sealed gas storage interlayer (300) is formed between the flexible accommodating chamber (100) and the housing (200). A one-way gas valve (230) is disposed on the housing (200). The inner diameter of the flexible accommodating chamber (100) changes as the gas pressure in the gas storage interlayer (300) changes. Each of two ends of the flexible accommodating chamber (100) is provided with an opening, and an accommodating bag (600) is disposed at the opening of one end in a sleeved manner. A shape maintaining structure used for keeping the shape when the inner diameter of the flexible accommodating chamber (100) changes is disposed in the flexible accommodating chamber (100). The shape maintaining structure is of a plurality of tapered bars (101) disposed along the axial direction of the flexible accommodating chamber (100) or a plurality of protrusive circular rings (102) disposed along the circumferential direction of the flexible accommodating chamber (100). An inflation bag (500) is also connected to the one-way gas valve (230). By arranging the shaping maintaining structure, the flexible accommodating chamber (100) can be supported, so that the flexible accommodating chamber (100) keeps a good shape structure when the gas pressure is changed, thereby facilitating the use by a user.La présente invention concerne un dispositif de pression de gaz comprenant une chambre de réception flexible (100) et un boîtier (200) manchonné à lextérieur de la chambre de réception flexible (100). Le boîtier (200) comprend un corps (210) et des bagues de serrage (220) disposées aux deux extrémités du corps (210). La ch