Abstract: The present invention relates to a pressure vessel (1) for a high pressure press, wherein the pressure vessel comprising a first sub-cylinder (4), a second sub-cylinder (6), pre-stressing means (8), and a securing member (16). The first and the second sub-cylinders (4, 6) are axially connected to form a cylinder body (2) for enclosing a high pressure medium. The first sub-cylinder (4) is in an outer wall provided with a first seat (22) for receiving a first part (24) of the securing member (16) and the second sub-cylinder (6) is in an outer wall provided with a second seat (26) for receiving a second part (28) of the securing member (16). The securing member (16) is fitted in the first and second seats (22, 26). The securing member (16), and the first and second scats (22, 26) are arranged such that the securing member (16), and the first and second scats (22, 26) cooperate to prevent separating axial movement between the first and the second sub-cylinders (4, 6).