The present invention provides a flow rate measurement device for measuring a volume of gas flowing through a gas supply system in which a plurality of appliances are connected. The flow rate measurement device according to the second embodiment comprises a flow rate sensor configured to detect a gas flow flowing through the gas supply system and a differentiator configured to differentiate the detected gas flow. A memory is provided in which profiles of gas consumption by appliances are storable in relation to identities of the appliances. The flow rate measurement device according to the present invention also comprises a first profile finder which is responsive to the differentiated gas flow to search for a profile from the stored profiles which corresponds to the detected gas flow. The device further comprises a second profile finder which is responsive to a failure by the first profile finder to find the corresponding profile from the stored profiles to analyze the detected gas flow to thereby determine an identity of at least one of the plurality of appliances.