Rectangular drawn case with extreme aspect ratio is widely used for electrical parts such as a lithium-ion battery container, semi-conductor case and so on. Additionally, from the recent trend towards miniaturization of the multi-functional mobile device, demands for rectangular case with the narrow width are increased. In this study, numerical and experimental approaches for the multi-stage deep drawing process have been carried out. Based on the research results of the width of 5.95mm model, finite element analysis for storage case of rectangular cup type was verified to the width of 4.95mm. Also, a series of manufacturing experiments for rectangular case is conducted and the deformed configuration of the rectangular drawn case are investigated by comparing with the results of the numerical analysis. And the modification of the initial blank is performed to minimize the trimmed material amount. By the application of the modified blank, the sound shape of the deformed parts is improved.