PROBLEM TO BE SOLVED: To provide a blood separator and an interface detection unit capable of detecting precisely and surely an interface between blood components with a simple constitution.SOLUTION: There is provided a blood separator 10 for distributing each blood component in a master bag separated by centrifugal separation into each slave bag. The blood separator 10 includes a blood transfer tube 20 for connecting the master bag to the slave bag, a transparent member 30 having a cylindrical part 31 capable of winding spirally the blood transfer tube around its outer peripheral surface, and an imaging part 40 installed so that the inner peripheral surface of the cylindrical part 31 can be imaged.SELECTED DRAWING: Figure 1
