Provided is a non-volatile memory device that includes a substrate including a plurality of active regions extending in a first direction and a plurality of element isolation trenches disposed between the active regions, a plurality of tunnel insulating layer patterns and a plurality of storage layer patterns sequentially disposed on the substrate, a plurality of blocking insulating layers and a plurality of gate electrodes disposed on the storage layer patterns and extending in a second direction perpendicular to the first direction, and first insulating layers including air gaps disposed between the active regions on the element isolation trenches and extending in the first direction, wherein the active regions include first active regions and second active regions adjacent to the first active regions, wherein a width of first air gaps is different from a width of second air gaps.