Abstract: In an automatic thin-film measuring apparatus, the zero point of a precision balance is corrected according to directions from a data processing unit before and after the weight of a semiconductor substrate is measured, the surface temperature of the semiconductor substrate laid on a pan of the precision balance is measured, and the weight of the semiconductor substrate is measured when the surface temperature reaches a predetermined value. Furthermore, the cycle of variations in the zero point is found when the zero point is corrected, and the weight measurement of the semiconductor substrate is conducted during an integer multiple of the change cycle. Therefore, it is possible to enhance the precision of the weight measurement and its reproducibility and to shorten the measurement time without being influenced by low-frequency vibrations.