A walking assistance robot comprising a link assembly configured to be worn by a user, the link assembly comprising: a first link configured to extend in a longitudinal direction along a leg of the user, the first link having a first coupling hole and a second coupling hole extending therethrough, the first coupling hole spaced apart from the second coupling hole , the first coupling hole receiving a first pin and the second coupling hole receiving a second pin ; and a second link connected to the first link such that a combination of the first link and the second link is extendible, the second link having a first slot and a second slot , the first slot receiving the first pin and the second slot receiving the second pin , wherein the first slot and the second slot have different shapes, wherein the first slot has a curved shape extending across the longitudinal direction, and the second slot extends in a straight line in the longitudinal direction, where the first link is supported by the second link , where the first link and the second link rotate and move linearly with respect to each other, characterized in that the first slot includes a mounting portion on which the first pin is mounted when the first link and the second link are aligned in a straight line; and a plurality of extension portions that extend from the mounting portion to be tilted in the longitudinal direction and support the first pin when the first link is rotated with respect to the second link . a first link configured to extend in a longitudinal direction along a leg of the user, the first link having a first coupling hole and a second coupling hole extending therethrough, the first coupling hole spaced apart from the second coupling hole , the first coupling hole receiving a first pin and the second coupling hole receiving a second pin ; and a second link connected to the first link such that a combination of the first link and the second link is extendible, the second link having a first slot and a second slot , the first slot receiving the first pin and the second slot receiving the second pin , wherein the first slot and the second slot have different shapes, wherein the first slot has a curved shape extending across the longitudinal direction, and the second slot extends in a straight line in the longitudinal direction, where the first link is supported by the second link , where the first link and the second link rotate and move linearly with respect to each other, characterized in that the first slot includes a mounting portion on which the first pin is mounted when the first link and the second link are aligned in a straight line; and a plurality of extension portions that extend from the mounting portion to be tilted in the longitudinal direction and support the first pin when the first link is rotated with respect to the second link . a mounting portion on which the first pin is mounted when the first link and the second link are aligned in a straight line; and a plurality of extension portions that extend from the mounting portion to be tilted in the longitudinal direction and support the first pin when the first link is rotated with respect to the second link . <EOS>