PROBLEM TO BE SOLVED: To easily perform movement such as rotation of an internal organ with low invasion.SOLUTION: A surgical instrument 1 includes: an instrument body 3 which is disposed rotatably around the long axis of a tubular sheath tube 2 penetrating a body surface tissue A of a patient and having an inner hole 2a opened inside and outside the patient body, inside the inner hole 2a of the sheath tube 2, and has a plurality of through holes 3a penetrating in the long axis direction and a plurality of arms 4 each of which is inserted into each through hole 3a of the instrument body 3 position-changeably in the length direction of the through hole 3a, and can be fixed to the instrument body 3. Each arm 4 includes, at a tip disposed inside the patient body, a fixing part 4b to be projected from an opening inside the patient body, and fixed to a surface of an internal organ.COPYRIGHT: (C)2014,JPO&INPIT【課題】低侵襲で簡易に臓器を回転等、移動する。【解決手段】患者の体表組織Aを貫通して体内外に開口する内孔2aを有する筒状の外套管2の内孔2a内に、該外套管2の長手軸回りに回転可能に配置され、長手軸方向に貫通する複数の貫通孔3aを有する器具本体3と、該器具本体3の各貫通孔3a内に、該貫通孔3aの長さ方向に位置変更可能に挿入され各位置で器具本体3に対して固定可能な複数のアーム4とを備え、各該アーム4が、体内側に配置される先端に、貫通孔3aの体内側の開口から突出させられて、臓器Bの表面に固定される固定部4bを備える手術器具1を提供する。【選択図】図1