To provide a medical long body improved in expandability of a narrow section and passability during delivery of the lumen of the living body.SOLUTION: An expansion member 130 included in a medical long body 10 includes a constricted state in which a plurality of blade parts 140 are arranged in a shaft 100 so as to be wound, and an expanded state expanding in the radial direction of the shaft. A linear member 150 has a deformation area 150A forming a protrusion in a natural state in a position in which the linear member is overlapped on the expansion member in the circumferential direction of the expansion member. The deformation area is arranged between the adjacent blade parts of the expansion member while being inhibited from forming a protrusion 155a in a constricted state of the expansion member, and forms a protrusion at an outer surface side of the expansion member due to that the expansion member is expanded in the radial direction in an expanded state of the expansion member.SELECTED DRAWING: Figure 3【課題】狭窄部の拡張性および生体管腔送達時の通過性の向上が図られた医療用長尺体を提供する。【解決手段】医療用長尺体１０が備える拡張部材１３０は、シャフト１００に複数の羽根部１４０を巻きつけるように配置された収縮状態と、シャフトの径方向に拡張した拡張状態と、を有し、線状部材１５０は、拡張部材の周方向において拡張部材と重なる位置に、自然状態で凸部を形成する変形領域１５０Ａを有し、変形領域は、拡張部材の収縮状態において、凸部１５５ａを形成することを阻害されつつ、拡張部材の隣り合う羽根部の間に配置され、拡張部材の拡張状態において、拡張部材が放射方向に拡張することにより、拡張部材の外表面側で凸部を形成する。【選択図】図３
