A catheter includes a hollow shaft, a multi-thread coil body covering the hollow shaft, and a cover member covering the multi-thread coil body. The multi-thread coil body includes a ring-shaped or substantially hollow cylindrical joint part in which distal ends of a plurality of element wires are joined in a circumferential direction, a coil main body located at a proximal side of the joint part in an axial direction, in which an outer shape of a cross section of each of the plurality of element wires is circular, and a transition part located between the joint part and the coil main body, in which a width of at least one of the plurality of element wires widens toward a distal end of the element wire.