PROBLEM TO BE SOLVED: To provide a walking motion assisting device capable of applying a walking assisting force as smoothly as possible even when a thigh reversal swing phenomenon contrary to the intention of a user occurs. SOLUTION: A thigh phase angle calculating means transmits a thigh phase angle φ (k) at a sampling timing S (k) (k is an integer of 1 or more) to a walking operation timing calculating means and a thigh phase angle φ (k). ) Is saved as the reference thigh phase angle φc, and the reference thigh phase angle φc saved instead of the thigh phase angle φ (k) at the timing S (k) is sent to the walking motion timing calculation means. It also has a stored data transmission process that maintains the reference thigh phase angle φc, the thigh phase angle at one timing is smaller than the reference thigh phase angle stored at that time, and the absolute value of the deviation is a predetermined threshold value. The stored data transmission process is performed only when the following conditions are satisfied, and the latest data transmission process is performed in other cases. [Selection diagram] FIG. 11【課題】ユーザーの意に反した大腿の逆転揺動現象が生じた場合であっても、歩行補助力の付与を可及的に円滑に行える歩行動作補助装置を提供する。【解決手段】大腿位相角算出手段は、サンプリングタイミングＳ(k)（ｋは１以上の整数）での大腿位相角φ(k)を歩行動作タイミング算出手段に送信し且つ大腿位相角φ(k)を基準大腿位相角φcとして保存する最新データ送信処理と、タイミングＳ(k)での大腿位相角φ(k)の代わりに保存されている基準大腿位相角φcを歩行動作タイミング算出手段に送信し且つ基準大腿位相角φcを維持する保存データ送信処理とを有し、一のタイミングでの大腿位相角がその時点で保存されている基準大腿位相角より小さく且つその偏差の絶対値が所定閾値以下である条件を満たす場合にのみ前記保存データ送信処理を行い、その他の場合には前記最新データ送信処理を行う。【選択図】図１１
