A catheter that prevents excessive concentration of stress while providing sufficient flexibility to a distal end portion of the catheter, even when the catheter is inserted and curved in patient's a blood vessel. Thus, breakage of the catheter at a radiopaque marker is prevented/reduced. The catheter includes a catheter tube and the radiopaque marker, which is disposed in the catheter tube. The radiopaque marker is fixed in the catheter so that a gap is provided between the radiopaque marker and the catheter tube in a radial direction of the catheter tube.