Provided are a blood sensor that is highly reliable and does not contaminate the interior of the main body of the device, a blood testing device and a blood analysis method. The blood sensor is provided with a plate-shaped base, a blood storage part set roughly in the center of the base, a supply path, one end of which is connected to the storage part and the other end of which is connected to an air pore, multiple detecting electrodes laid on one surface of the supply path connecting electrodes, each coming out of these detection electrodes, and skin detection electrodes in the storage part or near the storage part. The blood detecting device is provided with a skin detecting circuit that detects skin contact by measuring sensor conduction or impedance changes.
