A protector (1) is used by being attached to a puncture device (50). The protector (1) includes an outer tube (2) and an inner tube (9). The outer tube (2) includes an outer tube main body (3) including an outer tube lumen (4) for housing the puncture device (50), a holding part (5) for holding a hub (52), and an extended part (8) extended from the holding part (5) in a proximal end direction. The inner tube (9) includes an inner tube main body (10) and a lumen inclined part (12). The inner tube main body (10) is held in a proximal end side of the outer tube lumen (4) and movable in a proximal end direction of the outer tube lumen (4). The inner tube main body (10) includes an inner tube lumen (11) into which a tube (53) is inserted. In the lumen inclined part (12), an inner diameter of the inner tube lumen (11) gradually increases toward a distal end side of the inner tube main body (10). By moving the inner tube (9) in a distal end direction, the inner surface of the lumen inclined part (12) is abutted against the extended part (8), and the extended part (8) is biased by the lumen inclined part (12) in a direction in which a diameter of the tube (53) is reduced.
