A centrifugal separator includes a sample line and a rotating apparatus portion including a rotor that has a rotor chamber. The centrifugal separator centrifugally separates a sample by supplying the sample from the sample line into the rotor and driving to rotate the rotor in the rotor chamber and discharges the centrifugally separated sample from the rotor via the sample line. The centrifugal separator includes a sterilizing apparatus for sterilizing at least a portion with which the sample is brought into contact by making a sterilizing fluid flow through the sample line.