There is provided a method of manufacturing a non-volatile memory device including: alternatively stacking a plurality of insulating layers and a plurality of conductive layers on a top surface of a substrate; forming an opening that exposes the top surface of the substrate and lateral surfaces of the insulating layers and the conductive layers; forming an anti-oxidation layer on at least the exposed lateral surfaces of the conductive layers; forming a gate dielectric layer on the anti-oxidation layer, the gate dielectric layer including a blocking layer, an electric charge storage layer, and a tunneling layer that are sequentially formed on the anti-oxidation layer; and forming a channel region on the tunneling layer.