Abstract: A chain lock for round chain links, particularly for use in mining, consisting of preferably congruent part links, a center portion and a locking pin. The center portion is supported on cylindrical surfaces which form the base of a recess. The recess is provided in either inner side of the inner shank of the part links and undercuts both outer sides of the shank attached to it. The center piece has cylindrical supporting surfaces on opposite sides, and a pair of flat surfaces which are pierced by the cylindrical-surfaced supports. The ends of the center piece are supported in the receiver of the shanks when the center piece is inserted. The pin pierces the center piece at an angle and protrudes with its ends above and below the surfaces of the center piece to prohibit it from being rotated.