A problem of the present invention is to provide a flow rate measurement device which is capable of simplifying calculation, reducing the amount of memory necessary for calculation, absorbing variations resulting from manual operation or ignition state when the appliances are used alone or in combination, and improving appliance identification precision of appliances having similar characteristics with a configuration which extracts characteristics of appliances. The flow rate measurement device identifies the appliances with high precision by extracting characteristics of gas appliances from code sequences into which a differential conversion unit converts, at regular time intervals, differentials by a first calculation unit which calculates differentials at regular time intervals in the flow rates measured by a flow rate measurement unit and by a second calculation unit which calculates differentials at time intervals different from the first calculation unit.