Provided is a sensor chip for electrochemically measuring a concentration of an analyte in a blood sample. In one embodiment of the sensor, the sensor chip includes a substrate, and a preliminary measurement analyzer and a hematocrit value analyzer disposed on the substrate. The preliminary measurement analyzer includes a preliminary working electrode and a preliminary counter electrode. The hematocrit value analyzer includes a working electrode and a counter electrode. An oxidant of a redox substance is disposed on the preliminary measurement analyzer and the counter electrode. A reductant of a redox substance is disposed on the working electrode.