The present invention has an object of providing a technology capable of stopping and starting an internal combustion engine more preferably by restraining vibrations when the internal combustion engine stops and a scatter in crank angle when the internal combustion engine stops. For a period till an actual stop of the internal combustion engine since a stopping condition of the internal combustion engine was established, an air quantity of air flowing into a cylinder of the internal combustion engine is decreased when a number of revolutions of the engine is higher than a specified number of revolutions (S102) and is increased when the number of revolutions of the engine is equal to or lower than the specified number of revolutions (S106).