In a catheter 1 including an inner layer 20, a coil body 30 covering the inner layer 20, and an outer layer 50 covering the coil body 30, the coil body 30 is constituted using a plurality of single-strand wires (thin wires 41 and thick wires 42). The thick wires 42 of the coil body 30 are ground so that the cross-sectional shape thereof is formed to have a substantially semicircular shape, and an inner diameter ID and an outer diameter OD of the coil body 30 are constant in a length part in which the thick wires 42 are ground. In this manner, it is possible to prevent occurrence of unevenness on an outer peripheral surface or an inner peripheral surface of the catheter 1. In addition, when the catheter 1 is bent, the thin wires 41 move along the circular arc portion of the thick wires 42, which allows the catheter 1 to bend largely.
