The invention provides a calibration data generation apparatus, a calibration data generation method, and a flow rate control device. The calibration data generation apparatus can produce calibrationdata in a stepless mode without reassembling a fluid control valve. The calibration data generation apparatus produces the calibration data of a position sensor, which is arranged in a fluid control valve for controlling fluid; and outputs corresponding output value of a valve body that moves in a direction, wherein in the direction, the contact between the valve body and a valve seat is removed.The calibration data generation apparatus comprises a flow sensor, a pressure difference control mechanism, a temperature control mechanism, and a control unit, which comprises an output value obtaining part, a valve openness control part, and a calibration data generation part.