Abstract: An improved structure rope buckle having length adjustment capability that is comprised of a restraining base, a latch plate hinged onto the restraining base, a cramp block fitted into the two sides at the bottom end of the latch plate and capable of rotating along with the latch plate, and a torque spring installed under preloaded tension between the restraining base and the latch plate. The restraining base, the latch plate, and the cramp block are each punch formed from a single sheet of iron plate and, furthermore, the restraining base and the latch plate are sectionally aligned in a one-way teeth enmeshing arrangement. When the rope buckle of the present invention is in the normal state, the cramp block fitted into position at the bottom end of the latch plate has its teeth faces engaged against arresting blocks on the restraining base by the preloaded tension of the torque spring to thereby clutch the rope inserted between them.