A semiconductor device and a method for fabricating the same are provided to enable a bit line to be formed easily, increase a bit line process margin and reduce capacitance between the adjacent bit lines. The semiconductor device comprises: a first pillar and a second pillar each extended vertically from a semiconductor substrate and including a vertical channel region; a first bit line located in the lower portion of the vertical channel region inside the first pillar and the second pillar; and an interlayer insulating film located between the first pillar and the second pillar that include the first bit line.