The present invention relates to the distal end side of the outer coil, or the outer coil and the diameter of the core wire distal end portion 2B of the core wire to the coil of the inner coil A medical guide wire comprising inserted through, of the core wire distal end portion 2B diameter a rotation transmission performance distally due to reduction, there is a technical problem for improving the drilling performance of the lesion. A core wire distal end portion 2B is the structure of the connecting truncated cones 26 that meet certain relational expression concatenating truncated cones, the larger diameter outer diameter and small-diameter outer diameter of the connecting truncated cones 26 the outer diameter ratio, higher than the outer diameter ratio between the rear end large-diameter portion and the tip end small diameter portion of the inner coil 4, further than the outer diameter ratio of the rear large-diameter portion and the tip end small diameter portion of the outer coil, by higher, to reduce the rotation angle of the proximal side during rotating operation, thereby improving the drilling performance of the occlusion lesion by increasing the torsional moment distally.FIELD 6【課題】先端側の外側コイル内へ、又は外側コイルと内側コイルのコイル内へ芯線の細径の芯線先端部2Bを貫挿して成る医療用ガイドワイヤであって、芯線先端部2Bの細径化に伴う先端側への回転伝達性能と、病変部の穿孔性能を向上させる為の技術課題が存在する。【解決手段】芯線先端部2Bは、截頭円錐体を連接した一定の関係式を満たす連接截頭円錐体26の構造とし、連接截頭円錐体26の径大外径と径小外径の外径比を、内側コイル4の後端径大部と先端径小部との外径比よりも高く、さらに、外側コイルの後端径大部と先端径小部の外径比よりも、より高くすることにより、回転操作時に手元側の回転角度を減少させ、先端側へのねじりモーメントを増大させて閉塞病変部の穿孔性能を向上させることができる。【選択図】図6
