A flow path is formed in a cassette body of a blood component collection cassette. The cassette body includes a bulging structure in which at least a portion of the flow path is formed. A first gripped member, which is configured to be gripped by a first gripping member provided on a centrifugal separation device, is disposed on one surface of the bulging structure in a thickness direction thereof. A second gripped member, which is configured to be gripped by a second gripping member to which a load detection unit that is provided on the centrifugal separation device is fixed, is disposed on another surface of the bulging structure in the thickness direction thereof.
