PROBLEM TO BE SOLVED: To provide a motion assisting device that is light-weight, has a sufficiently long operating time, and is capable of assisting motion at appropriate timing.SOLUTION: A motion assisting device A comprises: a drive mechanism 9 for making force act on a body of a user U via a first appliance and a second appliance； posture detection units 7, 8, 3a for detecting the user U's posture； and a control unit 9d for controlling the drive mechanism. The drive mechanism 9 includes a transfer mechanism 9b configured to be capable of performing switching between a transfer state for transferring driving force based on a spring 9a to make a joint move so as to be in a predetermined state and a non-transfer state for storing driving force so as not to transfer but to enable the joint to move freely. The control unit 9d, when recognizing a predetermined trigger event on the basis of the user U's posture, automatically switches the transfer mechanism 9b to the non-transfer state.SELECTED DRAWING: Figure 1【課題】軽量で、稼働時間が十分に長く、適切なタイミングで動作の補助を行うことができる動作補助装置を提供する。【解決手段】動作補助装置Ａは、第１装具及び第２装具を介して、使用者Ｕの身体に力を作用させる駆動機構９と、使用者Ｕの姿勢を検知する姿勢検知部７，８，３ａと、駆動機構を制御する制御部９ｄとを備える。駆動機構９の伝達機構９ｂは、バネ９ａに基づく駆動力を伝達して関節を所定の状態となるように動作させる伝達状態と、駆動力を蓄積して伝達させずに関節を自由に動作可能とする非伝達状態とを切換可能に構成されている。制御部９ｄは、使用者Ｕの姿勢に基づいて所定のトリガーイベントを認識したときに、自動的に伝達機構９ｂを非伝達状態に切り換える。【選択図】図１
