A flow-meter comprising a flow rate detection circuit including a thermal flow rate sensor (10) disposed in a measurement flow passage for passing fluid to be measured therethrough, a temperature sensor circuit (12), a flow rate conversion circuit, and a storage means EEPROM. The storage means stores, for respective discrete temperature values, a plurality of individual calibration curves indicating as calibration curves the relations between electric outputs from the flow rate detection circuit and flow rates, and the individual calibration curves are prepared by using flow rates converted into those at a reference temperature. The flow rate conversion circuit performs interpolation based on temperatures measured by the temperature sensor circuit (12) and a plurality of individual calibration curves to obtain calibrated flow rate values corresponding to temperatures at measuring.