At least one distal side slope path is formed by penetrating an outer peripheral wall in the vicinity of a distal portion of a sheath main body and at least one proximal side slope path is formed by penetrating an outer peripheral wall in the vicinity of a proximal portion of the sheath main body. The at least one distal side slope path is inclined onto a proximal side from the outer peripheral surface to the inner peripheral surface of the sheath main body and the at least one proximal side slope path is inclined onto a distal side from the outer peripheral surface to the inner peripheral surface of the sheath main body. Therefore, blood is made to flow into a lumen and is made to flow out from the lumen along the blood flow in a blood vessel.
