Variable valve mechanism for internal combustion engine

A variable valve actuating device for an internal combustion engine, comprising:

• a valve having a valve head configured to selectively close an intake port or an exhaust port of a combustion chamber and a valve stem slidably supported by a cylinder head along an axial line thereof;
• a rocker arm including a pivoted part pivotally supported by the cylinder head, a cam follower driven by a cam of a camshaft, and a swing end;
• a valve lifter interposed between the swing end of the rocker arm and a stem end of the valve stem and slidably received in a support hole defined in the cylinder head along the axial line of the valve stem;
• and
• a switch member received in the valve lifter so as to be selectively moveable under oil pressure between a first position where the switch member abuts an end surface of the valve stem as the valve lifter is actuated by the cam and a second position where the switch member does not abut the end surface of the valve stem as the valve lifter is actuated by the cam;
• wherein the swing end of the rocker arm is engaged by an upper end part of the valve lifter via an engagement feature that prevents a rotational movement of the valve lifter relative to the swing end around the axial line of the valve stem.