To provide a dental opening holding tool which is excellent in operability capable of smoothly and easily guiding and holding an opening of a patient when dental treatment in an oral cavity is performed, and safety for protecting an operators fingers.SOLUTION: The insertion portion 2 is formed by carving a stepped groove 2a on the outer surface of a substantially conical shape whose outer diameter gradually increases from one end to the other end side, and an insertion portion 2 on the other end side of the insertion portion 2 And a hand grip portion 3 formed to rotate and push and pull the insertion portion 2 from the one end portion of the opposite outer surface of the insertion portion 2 toward the other end portion A planar sliding surface 2 b was formed. The stepped groove 2a is a threaded groove. The stepped groove 2 a is a plurality of independent circumferential grooves. A flange portion 4 having an outer diameter larger than the outer diameter of the other end side of the insertion portion 2 is provided at the boundary portion between the insertion portion 2 and the handgrip portion 3. An insertion hole (3a) through which the fingers can be inserted into the hand grip portion (3) is formed.(FIG.【課題】口腔内の歯科治療を行う際に、患者の開口を円滑且つ容易に誘導し保持できる操作性と術者の手指を保護する安全性に優れた歯科用開口保持具を提供する。【解決手段】一端部から他端側に向かって次第に外径が大きくなる略円錐形をなした外表面に段形の溝2aを刻んでなる挿入部2と、挿入部2の他端側に形成されて挿入部2を回転及び押引するための手把部3とを具備した歯科用開口保持具1であって、挿入部2の相対向する外表面の一端部から他端部に向かって平面状の滑走面2bを形成したこと。段形の溝2aが、ねじ状の溝であること。段形の溝2aが、独立した複数の円周溝であること。挿入部2と手把部3の境界部分に挿入部2の他端側の外径よりも大きい外径を有する鍔部4を設けたこと。手把部3内に手指を挿入できる挿入孔3aを形成したこと。【選択図】図5
