The end portion of the second inner exoskeleton member (117) mounted on the inner medial side is arranged so as to have a degree of freedom of ankle joint with respect to the flat plate member (121), and the end of the second inner exoskeleton member At the end portion of the outer exoskeleton member (112A), a convex portion CV receivable in the concave portion CC formed in the outer receiving member (125) is formed. In the closed leg posture, the convex portion CV of the second outer exoskeleton member (112A) is received in the concave CC of the outer receiving member (125), and the entire bottom surface of the flat plate member (121) is in contact with the floor surface. Upon transition from the closed leg posture to the open leg posture, the convex portion CV of the second outer exoskeleton member (112A) is disengaged from the concave CC of the outer receiving member (125) and the entire bottom face of the flat plate member (121) So that it is possible to maintain the state attached to it. When moving from the open leg posture to the closed leg posture, the leaf spring member (140) restores while contacting the convex portion CV of the second outer exoskeleton member (112A), and the convex portion CV is attached to the outer receiving member (125 ) To the concave CC of the concave portion.内甲側に装着される第2内側外骨格部材(117)の端部は、平板部材(121)に対して足関節の運動自由度を有するように配置され、外甲側に装着される第2外側外骨格部材(112A)の端部には、外側受容部材(125)に成形された凹部CCに受容可能な凸部CVが形成される。閉脚姿勢では、第2外側外骨格部材(112A)の凸部CVは、外側受容部材(125)の凹部CCに受容されており、平板部材(121)の底面全体が床面に接している。当該閉脚姿勢から開脚姿勢に移行すると、第2外側外骨格部材(112A)の凸部CVが、外側受容部材(125)の凹部CCから外れて、平板部材(121)の底面全体を床面につけた状態を保つことが可能となる。また、当該開脚姿勢から閉脚姿勢に移るときには、板バネ部材(140)が、第2外側外骨格部材(112A)の凸部CVと接しながら復元し、当該凸部CVを外側受容部材(125)の凹部CCに誘導する。
