Blood circuit adapter set and blood circuit

A blood circuit comprising:

• a blood line that is placed outside of a body and is configured to have blood flow therethrough;
• a first connector that includes a first end and a second end, and is attached at the first end thereof to the blood line and is configured to be connected at the second end thereof to a puncture needle;
• and
• a second connector that includes a first end and a second end, and is attached at the first end thereof to the blood line and is configured to be connected at the second end thereof to a puncture needle, the first connector and the second connector allowing connection of puncture needles of a type identical to each other;
• a first adapter that includes a first end and a second end, and is configured to be connected at the first end thereof to the first connector and connected at the second end thereof to a first port provided outside the blood circuit to allow communication between the first connector and the first port in a liquid-tight manner;
• and
• a second adapter that includes a first end and a second end, and is configured to be connected at the first end thereof to the second connector and connected at the second end thereof to a second port provided outside the blood circuit to allow communication between the second connector and the second port in a liquid-tight manner, wherein:
• the second end of the first adapter and the second end of the second adapter have different structures to prevent at least one of connection between the second end of the first adapter and the second port and connection between the second end of the second adapter and the first port, and
• the blood circuit is a single blood circuit that comprises the first connector and the second connector, and the first adapter and the second adapter are configured to be connected to the single blood circuit at a same time.