Abstract: A vortex shedding device for use in measuring air flow rate into an internal combustion engine includes a conduit having a passage that includes a venturi section. The venturi section has an inlet portion, a throat portion that has a smaller cross-sectional area than the cross-sectional area of the inlet portion, a converging portion between the inlet and throat portions and a diverging portion extending away from the throat portion toward the end of the passage. An elongated element is located in the throat portion of the passage for the purpose of generating vortices in air flowing through the passage. Preferably, the venturi section of the passage is of rectangular cross-section throughout and a honeycomb structure and screen are located in the inlet portion of the venturi section.