An object of the present invention is to provide a catheter capable of suppressing the end of the retrograde guidewire from entering the proximal shaft. The catheter 1 of the present invention includes a tubular mesh member 110 that can be expanded and contracted in the radial direction, a first hollow shaft 120 connected to the proximal end of the mesh member 110, a distal tip 130, and a core wire 150. The first hollow shaft 120 has a distal shaft 121 whose distal end is connected to the proximal end of the mesh member 110 and a proximal shaft 123 whose distal end is connected to the proximal end of the distal shaft 121. In the connecting portion 125 between the distal end side shaft 121 and the proximal end side shaft 123, an opening 126 is formed at the proximal end of the distal end side shaft 121. In the connecting portion 125, at the distal end of the proximal end side shaft 123, A sealing member that covers the outer periphery of the core wire 150 and allows the core wire 150 to slide therein is disposed.逆行性ガイドワイヤ端部が基端側シャフトへ迷入するのを抑制可能なカテーテルの提供を目的とする。 本発明のカテーテル１は、径方向に拡縮可能なチューブ状のメッシュ部材１１０と、メッシュ部材１１０の基端に接続された第１の中空シャフト１２０と、先端チップ１３０と、コアワイヤ１５０と、を備え、第１の中空シャフト１２０は、先端がメッシュ部材１１０の基端に接続された先端側シャフト１２１と、先端が先端側シャフト１２１の基端に接続された基端側シャフト１２３と、を有し、先端側シャフト１２１と基端側シャフト１２３との接続部１２５において、先端側シャフト１２１の基端には、開口部１２６が形成され、接続部１２５において、基端側シャフト１２３の先端には、コアワイヤ１５０の外周を覆い、かつ内部にコアワイヤ１５０が摺動可能な封止部材が配置されている。
