A semiconductor device includes: a first plug; a bit line which is in contact with the first plug and over the first plug and extended in one direction; a second plug including a first part adjacent to the bit line and a second part adjacent to the first plug; a double air gap which is disposed between the first part of the second plug and the bit line and includes a first air gap surrounding the first part of the second plug and a second air gap parallel to sidewalls of the bit line; and a capping layer suitable for capping the first and second air gaps.