A method for calibrating a temperature sensor, fitted onto a wireless-data-communicating wearable clinical thermometer, for sensing a target subject's body temperature and measuring the temperature, the temperature-sensor calibration method comprising: a storage step of storing a calibration coefficient computed for the fitted temperature sensor in a measuring-device storage medium; and a step of transmitting the calibration coefficient to a main unit of the clinical thermometer; and characterized by: a base-resistance acquisition step of sampling a base resistance value per the temperature sensor, and of acquiring the base resistance value; and a computation step of computing, based on a difference between the acquired base resistance value and a resistance value gauged with a standard temperature gauge, the calibration coefficient for calibrating the temperature; wherein the temperature sensor is fitted detachably from/reattachably onto the clinical thermometer; the clinical thermometer main unit is equipped with a computing device and a memory device; and the clinical thermometer main unit prepares, in the computing device, a plurality of resistance-temperature conversion tables by computing relationships between the base resistance value and actual temperature, based on calibration coefficients estimated beforehand. a storage step of storing a calibration coefficient computed for the fitted temperature sensor in a measuring-device storage medium; and a step of transmitting the calibration coefficient to a main unit of the clinical thermometer; and characterized by: a base-resistance acquisition step of sampling a base resistance value per the temperature sensor, and of acquiring the base resistance value; and a computation step of computing, based on a difference between the acquired base resistance value and a resistance value gauged with a standard temperature gauge, the calibration coefficient for calibrating the temperature; wherein the temperature sensor is fitted detachably from/reattachably onto the clinical thermometer; the clinical thermometer main unit is equipped with a computing device and a memory device; and the clinical thermometer main unit prepares, in the computing device, a plurality of resistance-temperature conversion tables by computing relationships between the base resistance value and actual temperature, based on calibration coefficients estimated beforehand. a base-resistance acquisition step of sampling a base resistance value per the temperature sensor, and of acquiring the base resistance value; and a computation step of computing, based on a difference between the acquired base resistance value and a resistance value gauged with a standard temperature gauge, the calibration coefficient for calibrating the temperature; wherein the temperature sensor is fitted detachably from/reattachably onto the clinical thermometer; the clinical thermometer main unit is equipped with a computing device and a memory device; and the clinical thermometer main unit prepares, in the computing device, a plurality of resistance-temperature conversion tables by computing relationships between the base resistance value and actual temperature, based on calibration coefficients estimated beforehand.