A flow rate measurement device, comprising: a flow rate measurement unit that is configured to measure a flow rate of a fluid flowing in a flow channel at a regular time interval; a calculation unit that is configured to calculate differentials at regular time intervals in the flow rate measured by the flow rate measurement unit; a flow rate classification table in which a plurality of differential classifications classified according to the magnitude of the differentials are associated with codes representing the respective classifications; a differential conversion unit that is configured to convert the differentials calculated by the calculation unit to the codes on the basis of the flow rate classification table; an appliance characteristic extraction unit that is configured to generate an appliance-characteristic code sequence representing a characteristic of an appliance from the codes obtained at regular time intervals by the differential conversion unit or extract a plurality of appliance characteristic flow rates representing characteristics of appliances from the flow rate measured by the flow rate measurement unit; and an appliance identification unit that is configured to compare at least either the appliance characteristic code sequence extracted by the appliance characteristic extraction unit with appliance-specific characteristic code sequences specific to appliances held in an appliance-specific characteristic information holding unit or a plurality of appliance characteristic flow rates extracted by the appliance characteristic extraction unit with a plurality of appliance-specific characteristic flow rates specific to appliances held in the appliance-specific characteristic information holding unit so as to identity the appliance, characterized in that the appliance characteristic extraction unit is configured, when codes within a predetermined range from among the codes obtained by the differential conversion unit appear continuously a first predetermined number of times, to store an average value of the flow rates until appeared continuously the first predetermined number of times as an intermediate stable flow rate of the appliance characteristic flow rates, and the appliance characteristic extraction unit is configured, when codes within a predetermined range from among the codes obtained by the differential conversion unit appear continuously a second predetermined number of times, to store an average value of the flow rates until appeared continuously the second predetermined number of times as a stable flow rate of the appliance characteristic flow rates. a flow rate measurement unit that is configured to measure a flow rate of a fluid flowing in a flow channel at a regular time interval; a calculation unit that is configured to calculate differentials at regular time intervals in the flow rate measured by the flow rate measurement unit; a flow rate classification table in which a plurality of differential classifications classified according to the magnitude of the differentials are associated with codes representing the respective classifications; a differential conversion unit that is configured to convert the differentials calculated by the calculation unit to the codes on the basis of the flow rate classification table; an appliance characteristic extraction unit that is configured to generate an appliance-characteristic code sequence representing a characteristic of an appliance from the codes obtained at regular time intervals by the differential conversion unit or extract a plurality of appliance characteristic flow rates representing characteristics of appliances from the flow rate measured by the flow rate measurement unit; and an appliance identification unit that is configured to compare at least either the appliance characteristic code sequence extracted by the appliance characteristic extraction unit with appliance-specific characteristic code sequences specific to appliances held in an appliance-specific characteristic information holding unit or a plurality of appliance characteristic flow rates extracted by the appliance characteristic extraction unit with a plurality of appliance-specific characteristic flow rates specific to appliances held in the appliance-specific characteristic information holding unit so as to identity the appliance, characterized in that the appliance characteristic extraction unit is configured, when codes within a predetermined range from among the codes obtained by the differential conversion unit appear continuously a first predetermined number of times, to store an average value of the flow rates until appeared continuously the first predetermined number of times as an intermediate stable flow rate of the appliance characteristic flow rates, and the appliance characteristic extraction unit is configured, when codes within a predetermined range from among the codes obtained by the differential conversion unit appear continuously a second predetermined number of times, to store an average value of the flow rates until appeared continuously the second predetermined number of times as a stable flow rate of the appliance characteristic flow rates.