A multi-articulated link knee joint includes: a knee unit in which an upper link member is structured to rotate relative to a lower link member by a multi-articulated link mechanism including a plurality of link members including the upper link member and the lower link member; a driven member to move in accordance with the rotation of the upper link member; a position detector for detecting the position of the driven member, the position detector provided at the lower link member; and an angle detector for obtaining the bending angle of the knee unit from the position of the driven member.