Abstract: The invention provides an apparatus for locking a pressure vessel. A locking pins-receiving member is installed on the front portion of said chamber, with locking pins-receiving holes being formed vertically through said locking pins-receiving member. A side of each supporting frame, which supports the door of said vessel, is fastened to the exterior of the door. Both ends of said supporting frame extends beyond the boundary of said door. A shifting member comprises a handle, locking pins, and connecting members connecting said handle to said locking pins. Locking pins are capable of shifting in piercing holes, which are formed at the end part of said supporting frames. Grooves extends longitudinally in a regular length from said pass-through holes towards the center of said supporting frames, such that said connecting members are capable of being inserted therein.