PROBLEM TO BE SOLVED: To provide a device for accurately estimating a posture of a person or the like based on an acceleration value measured by an acceleration sensor mounted on the trunk of the person or the like. An apparatus (10) for estimating the posture of a person or the like according to the present invention is attached to the trunk of a person or the like and has an acceleration sensor that measures acceleration values in three axial directions in time series and acceleration values in the three axial directions. Among them, the acceleration value in the three-axis direction when the person or the like is in the walking state is extracted, and the extracted acceleration value in the three-axis direction is used to determine the representative direction of the acceleration when the person or the like is in the walking state. A reference vector determining means for determining a reference vector to be represented, and a converted acceleration value that is a coordinate value in a reference coordinate space in which the direction of the reference vector coincides with a predetermined reference direction. It includes an acceleration value determining means and a posture estimating means for estimating the posture of a person or the like based on the converted acceleration value. [Selection diagram] Fig. 1【課題】人等の体幹に装着された加速度センサにより計測される加速度値に基づいて、精度良く、人等の姿勢を推定する装置を提供する。【解決手段】本発明の人等の姿勢を推定する装置１０は、人等の体幹に装着され、３軸方向の加速度値を時系列に計測する加速度センサと、３軸方向の加速度値のうち、人等が歩行状態にあるときに於ける３軸方向の加速度値を抽出し、抽出された３軸方向の加速度値を用いて、人等の歩行状態にあるときの加速度の代表方向を表す基準ベクトルを決定する基準ベクトル決定手段と、３軸方向の加速度値を基準ベクトルの方向が所定の基準方向に一致した基準座標空間に於ける座標値である変換後加速度値に変換する変換後加速度値決定手段と、変換後加速度値に基づいて人等の姿勢を推定する姿勢推定手段とを含む。【選択図】図１
