THERMAL FLOW RATE SENSOR

A thermal flow-rate sensor includes: a first temperature sensor 20 that detects the temperature at a specified location of the outer-wall surface of a pipe; a heat-transfer element 50 that is arranged on the outer-wall surface of the pipe in a state separated from the first temperature sensor 20, and that exchanges heat with a measurement medium by heating or cooling the outer-wall surface of the pipe 10; a second temperature sensor 30 that detects the temperature of a portion of the outer-wall surface of the pipe 10 that is heated or cooled by the heat-transfer element 50; and a control unit 60 that performs specified processing. A heat-flux sensor 40 is arranged between the heat-transfer element 50 and the outer-wall surface of the pipe 10 and directly detects heat flux between the heat-transfer element 50 and the pipe 10; and the control unit 60 detects the flow rate of the measurement medium based on the temperature that is directly detected by the first temperature sensor 20, the temperature that is detected by the second temperature sensor 30, and the heat flux that is detected by the heat-flux sensor 40.