The catheter 1 of the present invention has a tubular catheter body 2 made from a metal material. A groove 21 is formed in the outer periphery of the catheter body 2 in the longitudinal direction. This groove 21 is formed by plastically transforming the tubular wall of the catheter body 2 by plastic treatment. Thus, there is provided a catheter which has excellent followability and high ease of operation while maintaining torque transmissibility and pushability.