PROBLEM TO BE SOLVED: To provide a positioning instrument for an intramuscular injection which can easily select a proper intramuscular injection point with a simple work at a medical site when performing an intramuscular injection on a persons deltoid muscle.SOLUTION: A positioning instrument 10 for an intramuscular injection point at the time of performing an intramuscular injection on a persons deltoid muscle, includes: an acromion determining instrument for determining an intermediate point in a back and front direction of the acromial outside end of a shoulder a determining instrument 14 for determining an anterior and posterior axillary line connecting between the upper end of an anterior axillary line and the upper end of a posterior axillary line and a measuring instrument 13 for measuring a distance between the acromion determining instrument and the determining instrument for determining the anterior and posterior axillary line.COPYRIGHT: (C)2014,JPO&INPIT【課題】三角筋に筋注を行う際に医療現場で簡単な作業で容易に適正部位を選定できる位置決め器具を提供する。【解決手段】三角筋に筋肉内注射する際の筋注部位の位置決め器具10であって、位置決め器具10は、肩の肩峰外側端前後方向中間点を特定するための肩峰特定具と、前腋窩線の上端と後腋窩線の上端との間を結ぶ前後腋窩線特定具14とを備え、前記肩峰特定具と前後腋窩線特定具との間の距離を計測する計測具13を有する。【選択図】図1