An electronic device comprising: a printed circuit board including a first region and a second region, wherein the second region is adjacent to the first region; a ground line exposed on a top surface of the printed circuit board, said ground line including a boundary ground line for separating the first region and the second region, a first electronic element disposed in the first region; a second electronic element disposed in the second region; a first cover configured to shield the first electronic element, the first cover including a top surface, said first cover further having a boundary facing portion that is formed by alternating protrusion portions and recess portions; and a second cover configured to shield the second electronic element, the second cover including a top surface, said second cover further having a facing boundary portion that is formed by alternating protrusion portions and recess portions; wherein the protrusion portions of the second cover are aligned with respective recess portions of the first cover and wherein the protrusion portions of the first cover are aligned with respective recess portions of the second cover so that the first cover and the second cover tightly face each other; wherein at least one of the protrusion portions and the recess portions of the first cover and the second cover are formed to have a closed end; wherein the facing boundary portion of the first cover and the facing boundary portion of the second cover are received in the boundary ground line, wherein the top surface of the first cover has a size that corresponds to the first region and wherein the top surface of the second cover has a size that corresponds to the second region, and wherein the side surface of the first cover bends along a rim of the top surface of the first cover to a certain height and wherein the side surface of the second cover bends along a rim of the top surface of the second cover to a certain height. a printed circuit board including a first region and a second region, wherein the second region is adjacent to the first region; a ground line exposed on a top surface of the printed circuit board, said ground line including a boundary ground line for separating the first region and the second region, a first electronic element disposed in the first region; a second electronic element disposed in the second region; a first cover configured to shield the first electronic element, the first cover including a top surface, said first cover further having a boundary facing portion that is formed by alternating protrusion portions and recess portions; and a second cover configured to shield the second electronic element, the second cover including a top surface, said second cover further having a facing boundary portion that is formed by alternating protrusion portions and recess portions; wherein the protrusion portions of the second cover are aligned with respective recess portions of the first cover and wherein the protrusion portions of the first cover are aligned with respective recess portions of the second cover so that the first cover and the second cover tightly face each other; wherein at least one of the protrusion portions and the recess portions of the first cover and the second cover are formed to have a closed end; wherein the facing boundary portion of the first cover and the facing boundary portion of the second cover are received in the boundary ground line, wherein the top surface of the first cover has a size that corresponds to the first region and wherein the top surface of the second cover has a size that corresponds to the second region, and wherein the side surface of the first cover bends along a rim of the top surface of the first cover to a certain height and wherein the side surface of the second cover bends along a rim of the top surface of the second cover to a certain height.