The object of the invention is to provide an apparatus for noise depreciating in hermetic compressors. In the apparatus for noise depreciating for hermetic compressors of this invention, a diaphragm (45) is mounted to the interior surface of a chamber cover (40) through a welding process, thus dividing the interior of a muffling unit (30) into two chambers (31 and 31'). In a process of producing the above device, the chamber cover (40), integrated with the diaphragm (45), is locked to the top of a frame (2) having the chamber (31), with a packing (35) being interposed along the junction between the cover (40) and the frame (2). In the device of this invention, an inclined part (47) is formed along the edge of the diaphragm (45), thus allowing the diaphragm (45) to be easily and firmly integrated with the chamber cover (40) into a single structure by a welded material C during a process of welding the diaphragm (45) to the chamber cover (40). The apparatus of this invention remarkably improves work efficiency and productivity while assembling and forming such apparatus for noise depreciating in hermetic compressors.