PROBLEM TO BE SOLVED: To provide a surgical system for moving a compact treatment instrument at a reference direction, in the reference direction.SOLUTION: A surgical system includes: an arm body 30, a tip end of which is moved with respect to a base end in a three-dimensional space； a translation arm 35 that includes a base end-side link 61, the base end of which is continued from the tip end of the arm body, that rotationally turns about a first axis line L1 orthogonal to a prescribed reference direction D, and is configured to rotationally turn in an angle range including a retraction angle position and an advance angle position in which the tip end is located at a side separating from the first axis line in the reference direction with respect to the retraction angle position, and that includes a tip end-side link 62, the base end of which is continued from the tip end of the arm body, that rotationally turns about a second axis line L2 in parallel to the first axis line, and is configured to rotationally turn in an angle range including an evolute angle position and a spread angle position in which an angle formed with the base end-side link is larger than the evolute angle position； a translation arm drive part； and an instrument holding part 36 that can hold a surgical instrument having a long shaft 43 and a treatment instrument 44 in such an attitude that the shaft extends in a reference direction.SELECTED DRAWING: Figure 7【課題】コンパクトな基準方向における処置具を基準方向に移動させる機構を提供する。【解決手段】基端部に対して先端部を３次元空間内で移動するアーム本体３０と、基端部がアーム本体の先端部に連なり、所定の基準方向Ｄと直交する第１軸線Ｌ１周りに回動し、退避角度位置と退避角度位置よりも基準方向において第１軸線から離れる側に先端部が位置する進出角度位置とを含む角度範囲で回動するよう構成された基端側リンク６１と、基端部が基端側リンクの先端部に連なり、第１軸線と平行な第２軸線Ｌ２周りに回動し、縮閉角度位置と縮閉角度位置よりも基端側リンクと成す角の角度が大きい拡開角度位置とを含む角度範囲で回動するよう構成された先端側リンク６２と、を有する並進アーム３５と、並進アーム駆動部と、長軸状のシャフト４３と処置具４４とを有する外科用器具をシャフトが基準方向に延在する姿勢で保持可能な器具保持部３６とを備える。【選択図】図７
