PURPOSE: To provide the method for calibrating a thermometer, which can highly accurately calibrate various kinds of thermometers without using a long-stem-type standard platinum temperature measuring resistor that is expensive and weak against vibration, by using a highly accurately calibrated industrial temperature measuring resistor as the secondary standard.

CONSTITUTION: The scale of the temperature range of O-200°C of an industrial temperature measuring resistor specified in JISC 1604 and 1606 is calibrated at three fixed points. The intermediate temperature scale is regressed and valued. The industrial temperature measuring resistor adjusted in this way is made to be the standard thermometer, and the temperature ranges of various kinds of thermometers in 0-200°C are calibrated by a comparing method. This is the characteristic of the calibrating method of the thermometer. The scale of the temperature range of 0-30°C of the industrial temperature measuring resistor specified in JISC 1604 and 1606 is calibrated at two fixed points. The intermediate temperature scale is regressed and valued by the interpolation expression at the tripple points of water, i.e., the Ga points in ITS-90, and the industrial temperature measuring resistor adjusted in this way is made to be the standard thermometer. With this thermometer, the temperature ranges of various kinds of the thermometers in 0-30°C are calibrated by the comparing method. This is the characteristic of the calibrating method.