PROBLEM TO BE SOLVED: To provide an exchange tool capable of shortening the time required for an insertion operation and a withdrawal operation in a sensor insertion device, having a reusable structure in the device, and further being attachable to the device. SOLUTION: The sensor insertion device 1 is elastic that can be put into an energy storage state by elastically deforming a first elastic member 5, a second elastic member 6, and a first elastic member and a second elastic member. Energy variable mechanism 7, first holding mechanism 8a for holding the posture of the first elastic member in the energy storage state, and holding of the posture of the first elastic member by the first holding mechanism in the energy storage state and in the energy storage state After the needle is released, the second holding mechanism 8b holds the posture of the second elastic member while the needle member moves to the insertion position by the first elastic energy. [Selection diagram] Fig. 3【課題】センサ挿入装置において、挿入動作及び抜去動作に要する時間を短縮可能とし、装置に再利用可能な構成を備え、さらに装置に装着可能な交換具を提供する。【解決手段】センサ挿入装置１は、第１弾性部材５と、第２弾性部材６と、第１弾性部材及び第２弾性部材を弾性変形させることにより、エネルギー蓄積状態とすることが可能な弾性エネルギー可変機構７と、エネルギー蓄積状態において第１弾性部材の姿勢を保持する第１保持機構８ａと、エネルギー蓄積状態において、及びエネルギー蓄積状態での第１保持機構による第１弾性部材の姿勢の保持が解放された後、針部材が第１弾性エネルギーにより挿入位置まで移動する間、第２弾性部材の姿勢を保持する第２保持機構８ｂと、を備える。【選択図】図３
