A blood sensor usable both for a blood inspection device that performs puncture with a puncturing needle and for a blood inspection device that performs puncture with laser. In concrete, this invention comprises a sensor unit having a holder and a blood sensor mounted to the holder and a needle unit having a slidable puncturing needle. The needle unit provides a blood sensor block detachably fitted to the inside of the holder of the sensor unit. The blood sensor block is applied to a needle-puncturing type blood inspection device. The sensor unit from which the needle unit is removed is applied to a laser-puncturing type blood inspection device.
