This catheter has a longitudinal member having a longitudinal axis, a guide wire lumen which is formed along the longitudinal axis so as to pass through the guide wire to the long axis member at the tip portion of the long shaft member, the guide wire forming an opening slit along the longitudinal axis at the outer circumferential surface of the through lumen communicates disposed on the proximal end of the guidewire lumen the elongated shaft member, said is continuously formed along the longitudinal axis and an, an edge that protrudes toward a direction approaching each other from a position facing the edge of the opening. The width of the opening, wherein in a state where the edge portion not applied external force guide is a wire having a diameter of less passively changed by elastic deformation of the thermoplastic resin of said edge, the diameter of the long shaft member portion located on the opposite side of the opening in the direction of the degree of crosslinking of the thermoplastic resin is greater than the degree of crosslinking of the edge.本カテーテルは、長手軸を有する長軸部材と、前記長軸部材の先端部分において前記長軸部材にガイドワイヤを挿通するように前記長手軸に沿って形成されたガイドワイヤルーメンと、前記ガイドワイヤルーメンと連通して前記ガイドワイヤルーメンの基端に配され前記長軸部材の外周面において前記長手軸に沿ってスリット状の開口を形成し、前記長手軸に沿って連続的に形成されて前記開口の縁に対向した位置から互いに近づく方向に向かって突出された縁部と、を有する。前記開口の幅は、前記縁部に外力が掛かっていない状態において前記ガイドワイヤの直径以下であり、前記縁部の前記熱可塑性樹脂の弾性変形によって受動的に変化し、前記長軸部材の径方向において前記開口と反対側に位置する部分は、前記熱可塑性樹脂の架橋度が前記縁部の架橋度より大きい。
