A pulse shot-type flow rate control device including first and second shutoff valves, a tank, a pressure sensor, and a controller is caused to perform two or more processes. In each process, the controller repeats pulse shots of alternately causing the first shutoff valve and the second shutoff valve to open and close, changes a way of the pulse shots based on a pressure difference between the pressure after filling and the pressure after discharge, and controls a volume flow rate. In each process, the controller stores, as an optimal filling time, a filling time when the volume flow rate is controlled to a target flow rate, and opens and closes the first shutoff valve by using the optimal filling time in a first pulse shot in the next process.