The lower limb support device (10) has a curved back surface facing the ground, and is connected to the left and right foot portions (11) for individually placing the user's feet on the front surface side, and the respective foot portions of both feet. The left and right legs (13) extending along the vicinity of both of the user's legs and the user's waist are provided in the vicinity of the user's waist, and the left and right legs are individually rotatably supported, and the left and right legs A waist part (14) having left and right motors (15) for rotating the part forward and backward, respectively, and one leg part connected to one leg part while grasping the ground along the curved surface of the back surface of one leg part A control unit (16) that controls normal rotation or reverse rotation of the motor (15) of the waist (14) so that the other leg on the opposite side is rotated forward when kicking out and reverse when rotating. Along the curved surfaces of the back (12) of the left and right feet (11) Realizing walking by passive walking mechanism to catch the plane left and right feet on the ground at the rear surface (11) alternately.下肢支援装具（１０）は、地面と対向する裏面側が曲面であって、表面側に使用者の両足のそれぞれを個別に載せる左右の足部（１１）と、両足のそれぞれの足部と接続され、使用者の両脚のそれぞれの近傍に沿って延びる左右の脚部（１３）と、使用者の腰の近傍に設けられ、左右の脚部をそれぞれ個別に回転可能に支持すると共に、左右の脚部をそれぞれ正転又は逆転させる左右のモータ（１５）を有する腰部（１４）と、一方の足部の裏面の曲面に沿って地面を捉えながら、一方の足部と接続された一方の脚部とは反対側の他方の脚部を蹴り出し時には正転させ、振り出し時には逆転させるように腰部（１４）のモータ（１５）の正転又は逆転を制御する制御部（１６）と、を備え、左右の足部（１１）の裏面（１２）の曲面に沿って地面を左右の足部（１１）の裏面で地面を交互に捉える受動歩行機構による歩行を実現する。
