Problem: it is easy to hold the posture of the side lying position by rounding the human back.The posture retaining member 1 has a crotch portion inserted between the human crotch and a holding portion to be held in front of the human abdomen, and the crotch portion and the holding portion are adjacent to each other, and the holding portion is formed larger than the crotch part. It is possible to secure the posture of the episodic position by fixation of the human body by the force of the human body, and to secure the posture of the epicenter position and fixation by the patient himself.Diagram【課題】ヒトの背中を丸めて側臥位の姿勢を保持し易くする。【解決手段】体位保持具1は、ヒトの股の間に差し込まれる股部と、ヒトの腹部の前で抱きかかえられる抱え込み部とを有し、股部と抱え込み部とが隣接されていると共に抱え込み部が股部よりも大きく形成されている。ヒト自身が体位保持具1に抱きつくことで体位をヒト自身の力で容易に固定することができ、依って、ヒト・患者自身でエピの体位(穿刺体位)の確保と固定が可能となる。【選択図】図9