The invention relates to a semiconductor device, wherein a storage node contact hole is made large to solve any problem caused during etching a storage node contact hole with a small CD, a landing plug is formed to lower plug resistance. A semiconductor device according to the invention comprises: first and second active regions formed in a substrate, the first and second active being adjacent to each other, each of the first and second active regions including a bit-line contact region and a storage node contact region and a device isolation structure; a word line provided within a trench formed in the substrate; first and second storage node contact plugs assigned to the first and second active regions, respectively, the first and second storage node contact plugs being separated from each other by a bit line groove; and a bit line formed within the bit-line groove.