PROBLEM TO BE SOLVED: To provide a dental root canal cutting tool which is used by being attached to a dental hand piece and which can smoothly discharge a cutting material generated by cutting inside a root canal. SOLUTION: A working part 21 having a spiral cutting edge and narrowing toward the tip, a shaft 22 connected to the rear end of the working part 21, and a dental hand connected to the rear end of the shaft 22. A grip portion 23 connected to the piece, the shaft 22 is tapered toward the rear end of the working portion 21, and a taper portion 22a connected to the rear end of the tapered portion 22a. The dental root canal cutting tool 20 is composed of a straight portion 22b having the same diameter as the diameter of the thickest portion, and the smallest diameter of the tapered portion 22a is smaller than the diameter of the circumscribed circle of the rear end cross section of the working portion 21. .. [Selection diagram]【課題】 歯科用ハンドピースに取り付けて使用し、根管内を切削して生じた切削物の排出を円滑に行うことができる歯科用根管切削具を提供する。【解決手段】 螺旋状の切刃からなり先端に向かって細くなっている形状の作業部２１と、その作業部２１の後端に連なるシャフト２２と、そのシャフト２２の後端に連なり歯科用ハンドピースに接続される把持部２３と、を有し、前記シャフト２２が、作業部２１の後端に向かって細くなっているテーパー部２２ａと、そのテーパー部２２ａの後端に連なりテーパー部２２ａの最太部の径と同一径のストレート部２２ｂと、からなり、テーパー部２２ａの最細部の径が作業部２１の後端断面の外接円の径よりも小さい歯科用根管切削具２０とする。【選択図】 図２
