A blood test apparatus has a housing, a blood sensor, and a plurality of connectors. The blood sensor has a plurality of connection terminals that are electrically connected with each electrode of the electrode system and a reference terminal that serves as a reference. The plurality of connectors are configured to connect to the plurality of connection terminals and the reference terminal of the blood sensor attached at a predetermined position in the blood test apparatus, respectively. And also, relations between the reference terminal and each of the plurality of connection terminals are measured to identify the reference terminal automatically.
