An engine control apparatus includes a target air volume calculator which calculates a target air volume required by an engine, and an actual air volume calculator which calculates an actual air volume inhaled into a cylinder of the engine. The apparatus further includes an estimator which calculates the estimated value of subsequent actual air volume on the basis of a time lag from a time when the target air volume is calculated to a time when the actual air volume reaches the target air volume. The apparatus can accurately estimate an intake air volume inhaled into the cylinder to improve the controllability of the engine.