The present disclosure provides a manufacturing method of an electrode outer casing capable of improving a yield in a manufacturing method of an electrode outer casing which uses a laminated film and implementing an increase in productivity. The manufacturing method of an electrode outer casing disclosed herein includes a preparation step of preparing a multilayer laminated film which has at least a plurality of resin film layers, a transport step of transporting the laminated film to an unevenness forming section in order to form an uneven shape, a forming step of forming the laminated film in the unevenness forming section, and a cutting step of cutting the laminated film having been subjected to the forming step.