PURPOSE: To provide a molten-steel temperature measuring method wherein the measurement of a molten-steel temperature inside an arc furnace is performed by one operator from the insertion of a temperature detection probe into molten steel up to the processing of measured data and a measured value is processed with good accuracy without the intermediary of a human being.

CONSTITUTION: When a molten-steel temperature is measured, a temperature detection probe 3 is inserted into molten steel 2, and the molten-steel temperature is measured. Data on the molten-steel temperature detected by the temperature detection probe 3 is sampled at a cycle of 50 [msec], and it is taken into a programmable controller 5. The mean value of sampled data is used as the measured value of the molten-steel temperature and it is displayed on a display device 6.