A flange is provided at the opening metal of a pressure container, and it extends toward the periphery of the container body at the bonding part thereof at which it bonds to the container body. The liner of the pressure container has a self-sealing part at which it abuts the flange to be sealed up together. On the outer peripheral side of the self-sealing part, a ring-shaped constraint member is provided in the outer periphery of the liner, and the constraint member is to restrict the diameter expansion of the liner to be caused by the expansion of the container body. The liner has an easily-displaceable part that is readily elongable and deformable, at the outer periphery thereof in the radial direction of the self-sealing part.