An object is to provide a blood component collection system capable of collecting a desired blood component of high quality. A blood component collection system 1 comprises a centrifugal separator 20 centrifuging blood into a plurality of components, first line 21 for feeding the blood to the centrifugal separator 20, a second line 22 for releasing the blood component from the centrifugal separator 20, a temporary reservoir bag 26 for temporarily reserving the platelet concentrate, a leukoreduction filter 261 for separating and reducing leukocyte from the platelet concentrate, and a platelet collection bag 26 for reserving the platelet concentrate having passed through the leukoreduction filter 261. The blood component collection system 1 is constructed to feed the platelet concentrate in the temporary reservoir bag 26 to the platelet collection bag 26 through the leukoreduction filter 261, and then, feed plasma and collect the platelet remaining in the leukoreduction filter 261 (platelet concentrate from which leukocyte have been reduced) together with the plasma into the platelet collection bag 26.
