In a heating resistor type air flow measurement apparatus, flow correction data are read out from a primary memory and stored in a secondary memory, and then an air flow signal is calibrated by the flow correction data stored in the secondary memory when starting the apparatus up. The apparatus has a diagnosis unit, for determining whether or not the flow correction data stored in the primary memory are correct, so that the determination processing of the flow correction data by the diagnosis unit is performed at any time at least including the starting-up point of the apparatus. There is no fear that engine control based on abnormal flow correction data will continue.