Abstract: A safety device for automatically limiting the pressure in a container, which container is composed of a pot and a lid. The device is constituted by a seal member interposed between the pot and the lid to form a seal between the pot and the lid, the seal member having an annular form with an interior surface and an exterior surface and being provided with a recess in the exterior surface along a portion of its length. The recess creates a reduced cross section of the seal member for permitting a deformation of the portion under the action of pressure in the container, starting from a predetermined pressure value, to assure a break in the seal between the pot and the lid and depressurization of the container. The weakened cross section is formed by a combination of the recess in the exterior surface and at least one recess in the interior surface of the seal member.