A catheter 1 according to the present invention includes an inner tube 4, and a coil tube 5 disposed on an outer peripheral side of the inner tube 4 and configured to include a coil obtained by winding a wire. In addition, in the coil tube 5, a first coil and a second coil are arranged concentrically with each other. The first coil and the second coil have mutually different winding directions of the wire. Then, the inner tube 4 and the coil tube 5 are rotatable relative to each other around a central axis thereof. In addition, in a natural state where no external force is applied to the catheter 1, a gap is formed between the inner tube 4 and the coil tube 5.