For providing a blood separation device with which high-pitched noise is not generated even when a centrifugal separator is rotated before blood is introduced. A blood component separation device (100) includes a centrifugal bowl (19) including a stator (70) provided with an inlet (19a) and an outlet (19b) of blood or blood component and a rotor (75) provided rotatably with respect to the stator (70), a rotating and sliding portion between the stator (70) and the rotor (75) is sealed by pressing with predetermined pressing force, and the predetermined pressing force is 500 grams or less.
