Provided is a variable valve operating apparatus for an internal combustion engine, which can favorably improve the mounting environment of an actuator in the aspect of achieving the improvement of coolability and the reduction of stress. The apparatus includes a guide rail which is provided in the outer peripheral surface of a cylindrical part respectively fixed to a camshaft; a projection part which is disposed so as to be engageable and disengageable with the guide rail; and an actuator which is disposed so as to oppose the cylindrical part and can protrude the projection part toward the guide rail. At least a part of the actuator is disposed so as to fit in a oval-shaped region which is virtually obtained by linking a base circle of a main cam and a base circle of a main cam seen from the axial direction of the camshaft in a state in which the projection part is not protruded toward the guide rail.