A protector includes an outer tube and an inner tube. The outer tube includes an outer tube main body including an outer tube lumen for housing a puncture device, a holding part for holding a hub, and a lumen inclined part extended from the holding part. The inner tube includes an inner tube main body and an extended part. The inner tube main body is held in a proximal end side of the outer tube lumen and is movable in a proximal end direction of the outer tube lumen. The inner tube main body includes an inner tube lumen into which a tube is inserted. By moving the inner tube in a distal end direction, the inner surface of the lumen inclined part is abutted against the extended part, and the extended part is biased by the lumen inclined part in a direction in which a diameter of the tube is reduced.