Abstract: A cartridge for pressurized fluid. The cartridge includes a body having a cylindrical portion and a bottom having a concavity oriented toward the inside of the body. The connection between the bottom and the body is made by an annular seam. The particular structure of the connection zone provides a reduction in the diameter of the body for connection to a bottom of lesser diameter without creating zones of concentration of stresses. Another arrangement of the cartridge provides for the bottom to have a cylindrical portion that bears against the cylindrical end portion of the body, which makes it possible to create a rigid zone.