PROBLEM TO BE SOLVED: To secure flexibility of a diameter-reduced portion in a catheter having a diameter-reduced portion whose diameter is reduced from a proximal end side to a distal end side on an inner peripheral surface. SOLUTION: An inner layer 50, a braid 52 corresponding to a first reinforcing body wound radially outward of the inner layer, a reinforcing member 64 wound radially outward of the braid, an inner layer, a net. In a catheter including a group and an outer layer 62 that covers a reinforcing member, the inner layer has a reduced diameter portion 60 that decreases in diameter from the proximal end side toward the distal end side on the inner peripheral surface, and The thickness of the outer layer between the corresponding braid and the reinforcing member increases in at least a part from the proximal end side to the distal end side in the radial direction of the reduced diameter portion. Thereby, in the radial direction of the reduced diameter portion, the layer between the braid and the reinforcing member functions as a cushion, and the flexibility of the reduced diameter portion can be secured. [Selection diagram] Figure 2【課題】内周面において基端側から先端側に向かって縮径する縮径部を有するカテーテルにおいて、縮径部の柔軟性を担保する。【解決手段】内層５０と、内層の径方向における外側に巻き回された第１補強体に相当する編組５２と、網組の径方向における外側に巻き回された補強部材６４と、内層、網組、及び、補強部材を被覆する外層６２とを備えたカテーテルにおいて、内層が、内周面において基端側から先端側に向かって縮径する縮径部６０を有し、第１補強体に相当する編組と補強部材との間の外層の厚みが、縮径部の径方向において、基端側から先端側に向かう少なくとも一部で増加する。これにより、縮径部の径方向において、網組と補強部材との間の層がクッションとして機能し、縮径部の柔軟性を担保することが可能となる。【選択図】図２
