PROBLEM TO BE SOLVED: To provide a muscle activity level determination device that facilitates wearing of a measurement instrument and can determine a muscle activity level with a high degree of accuracy even in an exercise involving a vigorous motion.SOLUTION: A muscle activity level determination device comprises: a shape acquisition part 201 that acquires a muscle shape of a user when the user conducts a prescribed exercise a position specification part 202 that specifies a muscle position of the user when the user conducts the exercise a determination circuit 203 that refers to a determination reference showing each correspondence of the muscle position and the muscle shape to a muscle activity level and then determines the muscle activity level using the muscle position specified by the position specification unit 202 and the muscle shape acquired by the shape acquisition part 201 and an output part 204 that outputs the activity level determined by the determination circuit 203.SELECTED DRAWING: Figure 6COPYRIGHT: (C)2017,JPO&INPIT【課題】計測具の着用が容易で、かつ動きが激しい運動においても筋肉の活動量を高精度に決定できる筋活動量決定装置を提供すること。【解決手段】ユーザが所定の運動をしている時の前記ユーザの筋肉の形状を取得する形状取得部201と、前記ユーザが前記運動をしている時の前記ユーザの筋肉の位置を特定する位置特定部202と、筋肉の位置及び筋肉の形状と筋肉の活動量との対応を示す決定基準を参照し、位置特定部202で特定された前記筋肉の前記位置及び形状取得部201で取得された前記筋肉の前記形状を用いて、前記筋肉の活動量を決定する決定回路203と、決定回路203で決定された前記活動量を出力する出力部204と、を備える。【選択図】図6