A blood component collection apparatus comprises a blood component collecting circuit which includes an anticoagulant line for feeding an anticoagulant and a line for collecting an initial flow of collected blood. In the blood component collection apparatus, air is intermediately present between the anticoagulant and the blood in the passage of a blood collection needle side line, after a priming operation is performed in which anticoagulant is supplied from the anticoagulant line toward the side of a centrifugal separator in the blood collection needle side line through a branch connector and after an initial flow collecting operation is performed in which the initial flow of blood is collected.
