A placement device for a blood vessel treatment instrument has an introducer sheath functioning as an outer tube, and also has an inner tube. The introducer sheath has a flexible tube-shaped sheath body and a hub into which the base end of the sheath body is inserted. The hub takes-up the base end of the sheath body into the hub by way of take-up shafts while slitting the base end of the sheath body by cutting blades, and thus the length of extension of the sheath body from the hub can be shortened.
