A semiconductor device includes an interlayer insulation layer on a semiconductor substrate, a via plug and a wiring line on the via plug, in the interlayer insulation layer, the via plug and the wiring line coupled with each other and forming a stepped structure. The semiconductor device includes a first air-gap region between the interlayer insulation layer and the via plug, and a second air-gap region between the interlayer insulation layer and the wiring line. The first air-gap region and the second air-gap region are not vertically overlapped with each other.