A thermal flow meter comprising: a subsidiary passage having an opening portion through which a fluid to be measured is to be drawn in; and a sensor element disposed in the subsidiary passage , the sensor element for measuring a flow rate of the fluid to be measured , wherein the sensor element includes: a semiconductor substrate ; an electrically insulating film formed on the semiconductor substrate ; a cavity portion formed in the semiconductor substrate ; a heating resistor formed on the cavity portion via the electrically insulating film ; a heating temperature sensor for detecting heating temperature of the heating resistor ; a driving circuit for controlling the heating temperature of the heating resistor using the temperature detected by the heating temperature sensor ; a wiring portion connected electrically to the heating resistor ; and a wiring portion for leading electrically from the heating temperature sensor to an outside of the cavity portion wherein the heating resistor and the wiring portion have a connecting portion for connecting therebetween, the connecting portion including a throttle portion; and wherein the heating temperature sensor is disposed along the throttle portion so as to surround a periphery of the heating resistor , characterized in that , the wiring portion connecting the heating temperature sensor has a wire width on the cavity portion wider than a wire width of the heating temperature sensor ; the throttle portion comprises two recesses formed by the heating resistor and the wiring portion connecting the heating resistor ; and the heating temperature sensor is disposed along the shape of the recesses . a subsidiary passage having an opening portion through which a fluid to be measured is to be drawn in; and a sensor element disposed in the subsidiary passage , the sensor element for measuring a flow rate of the fluid to be measured , wherein the sensor element includes: a semiconductor substrate ; an electrically insulating film formed on the semiconductor substrate ; a cavity portion formed in the semiconductor substrate ; a heating resistor formed on the cavity portion via the electrically insulating film ; a heating temperature sensor for detecting heating temperature of the heating resistor ; a driving circuit for controlling the heating temperature of the heating resistor using the temperature detected by the heating temperature sensor ; a wiring portion connected electrically to the heating resistor ; and a wiring portion for leading electrically from the heating temperature sensor to an outside of the cavity portion a semiconductor substrate ; an electrically insulating film formed on the semiconductor substrate ; a cavity portion formed in the semiconductor substrate ; a heating resistor formed on the cavity portion via the electrically insulating film ; a heating temperature sensor for detecting heating temperature of the heating resistor ; a driving circuit for controlling the heating temperature of the heating resistor using the temperature detected by the heating temperature sensor ; a wiring portion connected electrically to the heating resistor ; and a wiring portion for leading electrically from the heating temperature sensor to an outside of the cavity portion wherein the heating resistor and the wiring portion have a connecting portion for connecting therebetween, the connecting portion including a throttle portion; and wherein the heating temperature sensor is disposed along the throttle portion so as to surround a periphery of the heating resistor , characterized in that , the wiring portion connecting the heating temperature sensor has a wire width on the cavity portion wider than a wire width of the heating temperature sensor ; the throttle portion comprises two recesses formed by the heating resistor and the wiring portion connecting the heating resistor ; and the heating temperature sensor is disposed along the shape of the recesses . <EOS>