We reported ergonomic practice for the development of a swing chair to induce drowsiness and We reported ergonomic practice for the development of a swing chair to induce drowsiness and relaxation. In the process of functional examination and improvement of the chair, we examined not only relaxation. In the process of functional examination and improvement of the chair, we examined not only the chair angles but also the swinging amplitude to enhance the effect of using the chair. The subsequent the chair angles but also the swinging amplitude to enhance the effect of using the chair. The subsequent verification process suggested that drowsiness and relaxation could be induced by adjusting the position verification process suggested that drowsiness and relaxation could be induced by adjusting the position and swinging speed of the chair according to an individual's preference. Finally, the developed swing and swinging speed of the chair according to an individual's preference. Finally, the developed swing chair was commercialized and sold, and a survey of its customers confirmed that they were highly chair was commercialized and sold, and a survey of its customers confirmed that they were highly satisfied with the product. From these practices, the role and issues of ergonomics will be discussed in satisfied with the product. From these practices, the role and issues of ergonomics will be discussed in terms of developing products that have an impact on the human body and mind. terms of developing products that have an impact on the human body and mind. 眠気やリラックス感を誘導するための揺れるチェア(スウィングチェア)の開発において人間工学の面 から取り組んだことを報告する．機能検討・改善のプロセスにおいては，揺れの効果を高めるためのチェ アの姿勢，揺れの振幅などを検討した．効果検証のプロセスにおいては，個々にとって望ましいチェア の姿勢や速度に調整することによって，眠気やリラックス感を誘導できることが示唆された．最終的に 開発されたスウィングチェアは製品化・販売され，購入者に調査を行った結果，製品の満足度も高いこ とが確認された．これらの実践から，人間の心身の状態に働きかける製品の開発における人間工学の役割・ 課題について議論する． (キーワード：人間工学の実践，製品開発，誘眠，姿勢，満足度)