A variable valve operating device for an internal combustion engine includes a cam carrier supported on a camshaft and shifting switching pins that are advanced into and retracted out of shift lead grooves defined in the cam carrier. The shift lead grooves include shift groove side walls having shift groove side wall surfaces from shift starting inflection regions of the cam carrier to shift ending inflection regions thereof. The shift groove side walls include particular shift groove side walls extending from axial positions of the shift starting inflection regions toward shift intermediate regions and also extending from circumferential positions of the shift intermediate regions disposed between the shift starting inflection regions and the shift ending inflection regions toward the shift starting inflection regions. The side walls have slanted outer circumferential surfaces extending from the circumferential positions progressively deeper toward groove bottom surfaces and reaching the shift starting inflection regions.