When an acceleration flag is not set, an amount of target rotation tvttbb1 of a variable valve mechanism is set on the basis of an amount of intake air and an engine speed. On the other hand, when the acceleration flag is set, an amount of target rotation of the variable valve mechanism is set on the basis of the engine speed, a cooling water temperature, and an atmospheric pressure. As described above, when the acceleration flag is not set, i.e., when the amount of intake air does not change excessively, the amount of target rotation based on the amount of intake air is used, so that the valve timing can be controlled appropriately.