A catheter is provided that includes a catheter body, a catheter hub, and a securing member disposed in the catheter hub to clamp the catheter between the securing member and the catheter hub. The securing member has an outer peripheral surface making contact with and stretching an inner peripheral surface of the catheter body. The catheter includes a recessed relief portion into which a thickness of the catheter body is inserted, the relief portion being partially provided circumferentially in an inner peripheral surface of the catheter hub.
