Abstract: A joint lock with improved structure is disclosed. The joint lock includes a steel rope wire, a latching member for latching the steel rope wire in position, a bendable covering sleeve for covering the steel rope wire, and a lock device. The lock device is composed of a locking member and a locking plug, in which the locking member is fixed on one end of the rope wire and the locking plug is fixed on the other end of the rope wire. The latching member is composed of a plurality of fork chucks and a latching ring having its inner diameter slightly larger than the outer diameter of the steel rope wire and being slidable along the rope wire. The fork chucks is a flexible outward fork-like structure in order to engage with the inner wall of the covering sleeve. The covering sleeve is composed of a plurality of joint units for covering the rope wire so that the rope wire is bendable correspondingly when the covering sleeve is bent.