A centrifugal separation device of a blood component collection system comprises a data acquisition unit that acquires initial data A, an estimated data calculation unit that calculates estimated data B on the basis of the initial data A, a reaction force calculation unit which calculates a reaction force of a first applied load measurement unit on the basis of the estimated data B, and an internal pressure calculation unit that calculates an internal pressure of the first applied load measurement unit, based on the reaction force and a load detected by a first load detecting unit.
