A non-volatile memory device is provided wherein a lower molding layer is formed on a substrate; a first horizontal interconnection is formed on the lower molding layer; an upper molding layer is formed on the first horizontal interconnection; a pillar is formed connected to the substrate by vertically passing through the upper molding layer, the first horizontal interconnection and the lower molding layer. The pillar has a lower part and an upper part, wherein the lower part is disposed on the same level as the first horizontal interconnection and has a first width and the upper part is disposed on a higher level than the first horizontal interconnection and has a second width different from the first width.