To provide a method and device by which a mass flow controller (MFC) can be calibrated efficiently so that the MFC may have high supply accuracy and responsiveness.

The method for calibrating the MFC which is installed to a fluid passage through which a gas fluid is made to flow and provided with a flow control valve which controls the valve travel of a valve with a driving signal and a sensor section which outputs the flow rate of the gas fluid as a flow rate signal includes a step of adjusting the driving signal so that the flow rate of the fluid may become a prescribed value based on the flow rate signal outputted from a flowmeter which outputs the flow rate of the gas fluid as the flow rate signal and calculating the control constant which controls the output pattern of the driving signal based on the flow characteristic of the MFC. The method also includes a step of measuring a prescribed flow rate of the gas fluid by means of the flowmeter and the sensor section of the MFC and calculating the correcting amount of the detection characteristic of the MFC based on the obtained flow rate and the detection characteristic of the MFC.