Abstract: A sealing cap for pressurized gas containers, in particular for 500 kg chlorine containers, has at least two, preferably four, retaining claws, which engage in an existing bead on the pressurized gas container and effect the sealing. The retaining claws are connected to the sealing cap via a rod having a mount, the rod, at the opposite end, having a screw thread with a lock nut. A seal of resistant material is advantageously guided in a groove of the sealing cap. Furthermore, the sealing cap may have a pressure gage, a discharge valve and handles.