A control device for an internal combustion engine including 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 plane cam shape portions, at the camshaft, have valve lift characteristics different from each other, have respective cam faces parallel to a rotation axis of the camshaft, and are spaced apart from each other. The transitional shape portion is between two adjacent ones of the plane cam shape portions and has a curved cam face which connects the cam faces of the two plane cam shape portions. The cam switching mechanism switches between the valve lift characteristics for an intake valve by selecting one of the plane cam shape portions via the transitional shape portion.