A surgical instrument comprising a machined member (1) and a protective member (8) and used in dental surgery, wherein the machined member (1) includes a connection region (3) and a hollow cylindrical head (4). An operating region (6) for machining and / or cutting bone is formed at the head tip (5) of the hollow cylindrical head (4), and the protective member (8) Bearing element of the machined member (1), at least partially surrounding the hollow cylindrical head (4), wherein the protective member (8) extends at least partially into the hollow cylindrical head (4) A surgical instrument that is rotatably coupled to (7). [Selection] Figure 1機械加工部材（１）と保護部材（８）とを備え、歯科手術で用いられる手術用器具であって、前記機械加工部材（１）が、接続領域（３）と中空円筒ヘッド（４）を有するシャフト（２）を有し、骨を機械加工および／または切削する動作領域（６）が、前記中空円筒ヘッド（４）のヘッド先端部（５）に形成され、前記保護部材（８）が、前記中空円筒ヘッド（４）を少なくとも部分的に取り囲み、前記保護部材（８）が、前記中空円筒ヘッド（４）内に少なくとも部分的に延在する、前記機械加工部材（１）の軸受要素（７）に回転可能に連結される、手術用器具。【選択図】図１
