An adapter set that is attached to artery-side and vein-side shunt connectors 18a, 18v that are provided on a blood circuit 10. The adapter set comprises: an artery-side adapter 20a that has one end thereof connected to the artery-side shunt connector 18a, has the other end thereof connected to a drainage port 56d that is provided on the outside of the blood circuit 10, and thereby connects the artery-side shunt connector 18a and the drainage port 56d fluid tight； and a vein-side adapter 20v that has one end thereof connected to the vein-side shunt connector 18v, has the other end thereof connected to a supply port 56s that is provided on the outside of the blood circuit, and thereby connects the vein-side shunt connector 18v and the supply port 56s fluid tight. The structure of the other end of the artery-side adapter 20a and the structure of the other end of the vein-side adapter 20v are different.
