A blood sampling device (10) configuring a blood bag system (12) includes: a hollow needle (80) that can penetrate through a rubber plug (202) of a blood sampling tube (200) inserted into a blood sampling holder (78) ； a hub (76) that includes a needle supporting unit (90) for supporting a base end side of the hollow needle (80) and to which the blood sampling holder (78) is rotatably attached； a needle cover (82) made of rubber that is externally fitted to the needle supporting unit (90) while covering a tip side of the hollow needle (80)； and a cap (84) arranged on the needle supporting unit (90) in such a manner that the cap (84) can come into contact with the needle cover (82) and is independent of the blood sampling holder (78).
