PROBLEM TO BE SOLVED: To obtain a retractor for retaining and maintaining an incision in the oral cavity in oral surgery, but there is no appropriate retractor. Kind Code: A1 A retractor (1) for keeping an incised cut open when a gum is cut, which comprises a pair of left and right arm parts and the cut end formed at the tip of the arm parts. And a fulcrum part that is formed at an end portion of the pair of arm parts on the opposite side of the pressing part and that connects the pair of arms so as to be openable and closable, and the fulcrum part as a fulcrum. When the arm portion is elastically deformed in the direction in which the holding portion is closed, a material that causes an elastic restoring force in the arm portion in the direction in which the holding portion opens is further used, and further, the holding portion and the fulcrum of the arm portion. The shape between the parts is characterized by a shape corresponding to the arrangement of the teeth. [Selection diagram] Figure 7-2【課題】口腔外科において、口腔内の切創を開創維持する開創器が求められていたが、適切な開創器が存在しなかった。【解決手段】歯茎を切創した際、切創された切り口を開いた状態に維持する開創器（１）であって、左右一対のアーム部と、該アーム部の先端に形成され前記切り口を押さえる押さえ部と、前記一対のアーム部の前記押さえ部とは逆側の端部に形成され且つそれら一対のアーム同士を開閉可能に連結させた支点部とを備え、前記支点部を支点として前記押さえ部を閉じる方向に前記アーム部を弾性変形させた場合に、前記押さえ部が開く方向に前記アーム部に弾性復元力が発生する材料であり、さらに、前記アーム部の前記押さえ部及び前記支点部間の形状は歯の配列に応じた形状であることを特徴とする。【選択図】図７－２
