To enable to perform an absolute flow rate calibration with high accuracy by a process gas in a flow rate control device.

The system comprises a gas flow path 30 between a first shutoff valve 21 and a second shutoff valve 22, an evacuation flow path 31 connecting an inlet of a vacuum pump 14, a third shutoff valve 23 mounted on the evacuation flow path 31, a pressure sensor 11, a temperature sensor 12 and a fourth shutoff valve 24, and connecting the above, and a calibration control device which memorizes a volume value of a predetermined space comprising of an outlet of a mass controller 10 of compression factor data of the gas species, the second shutoff valve 22 and the third shutoff valve 23. At the first measurement and the second measurement, a mass G1 is obtained from a pressure P1, a temperature T1, the first compression factor Z1 corresponding to these, and a volume V, and the mass G2 is obtained from the pressure P1, the temperature T2, the second compression factor Z2 corresponding to these, and the volume V at the second measurement, the absolute flow rate of the mass flow controller 10 is calibrated from the difference of the mass G1 and the mass G2.