PURPOSE: To effect easy and automatic measurement of a specimen provided with a plurality of constant measuring position patterns, by installing controlling unit of an electrically driven table available for external control and displacements in fore and aft and RH and LH directions, measuring position operating unit, apparatus controlling unit and storing apparatus.

CONSTITUTION: For automatic measurement, a specimen 4 is laid on an electrically driven table 5 and the measurement is started by setting a specimen observing unit 1 available for confirmation of an X-ray beam protected position at the measurement starting point. And, at the beginning, the measured position is taken out of a storing apparatus 9 and check is made for termination of the automatic measurement. Next, the measured position is converted to the absolute co-ordinates and by the converted position data, the table 5 is controlled and thickness is measured.