Abstract: The invention forming the subject matter hereof comprises a flow measuring device for use in fluid-carrying conduits characterized by an elongate housing member including a longitudinally-extending slot communicating the interior thereof and opening upstream, a first tubular impact probe mounted within the housing and having a port in the wall thereof opening in a direction other than toward the slot in the latter, and a second tubular suction probe mounted inside the housing alongside the impact probe, the suction probe also including a port in the wall thereof facing downstream.