Patent ID: 6952961

Claim:
An air flow rate measuring device adapted to be mounted on an intake pipe of an internal combustion engine for measuring a flow rate of air flowing through a main passage inside the intake pipe, said device comprising: a base having its one end directed along an axial direction of said main passage toward an upstream side of air flowing therein, and its other end directed toward a downstream side of the air, said base being formed with a groove which is bent at a location between the opposite ends thereof; and a circuit module including a support substrate and a detection element installed one surface of said support substrate for detecting said flow rate of air, said module being joined to said base in a face-to-face relation with respect to each other to form an auxiliary passage in cooperation with said groove; wherein said detection element on said one surface of said support substrate is exposed to air in said auxiliary passage, and the other surface of said support substrate is exposed to air in said main passage.