A display device and a manufacturing method thereof are provided to prevent the moisture and oxygen from being inputted by forming a moisture absorbent on a cover board before forming a protective film. A display device is prepared on an insulating board(100). A cover board(120) is welded to the insulating board to face. The cover board prevents the inflow of the moisture and oxygen. A sealing material(130) is formed along an edge between the cover board and the insulating board. The sealing material is a kind of the sealant which prevents the oxygen or the moisture from being inputted through a space formed by the insulating board and the cover board. A protective film(140) is interposed between the insulating board and the cover board to cover the display device. The protective film couples the insulating board with the cover board.
