Abstract: An auxiliary lock comprising a lock body for extension through an opening in the closure to be secured; there being a stop forming element on one end of said lock body for engaging one side portion of said door to limit the extension of said lock body therethrough, as well as to stabilize same in position. A bolt is presented for projecting through a bore in the extended portion of said lock body, in generally axially perpendicular relationship thereto. One end of said bolt is enlarged to limit its projection through said lock body bore, and the other end is received within a socket provided in the structure adjacent the door. A lock is engageable upon said bolt between said lock body and said socket.