Control device for an internal combustion engine with a variable lift valve mechanism

A control device for an internal combustion engine includes: a camshaft of the internal combustion engine; a plurality of plane cam shape portions; at least one transitional shape portion; a cam switching mechanism; a cam position sensor; and a control section. The plurality of plane cam shape portions are provided at the camshaft, have valve lift characteristics different from each other. During transition from a valve lift to another, the engine control modifies the ignition timing, the fuel injection time and the duty ratio of the sub-throttle valve drive motor for smoothing the transition.