PURPOSE: To improve controllability by transferring an engine speed feedback control amount secularly to a correction memory based on a deviation between a target air amount and the actual intake air amount and controlling the intake air amount by the target intake air amount and the correction memory value in accordance with the engine speed feedback control amount.

CONSTITUTION: A target intake air amount Qo is output from a node N2, and a deviation between the target intake air amount Qo and the actual intake amount QA is obtained in a node NB. This deviation is input to a control arithmetic part 37, and the larger this deviation is, the larger a correction flow amount ΔQ is increased and the correction flow amount ΔQ is output after calculation for obtaining zero value of ΔQ when it is the absolute value of the deviation or less. A switch S2 is actuated in each predetermined period, and when this switch is in operation, the correction flow amount ΔQ is transferred to a correction memory 38 from an engine speed feedback control amount QNFB of an arithmetic part 34, and stored. Processing is finished by subtracting ΔQ from the engine speed feedback control amount QNFB in the arithmetic part 34 and by adding the ΔQ to a memory valve QMFB in the correction memory 38.