An electrode assembly and a method of manufacturing the same are provided. The electrode assembly includes a first electrode laminate formed by stacking one or more electrode units having a first area, and a second electrode laminate formed by stacking one or more electrode units having a second area different from the first area. The first electrode laminate and the second electrode laminate are stacked on each other in a direction perpendicular to a plane and have a step portion formed by a difference in areas of the first and second electrode laminates, the step portion is present on at least one side of four sides of the electrode assembly, at least one step portion includes at least a portion of tape taped across a stacked side, and the portion of tape has a form corresponding to a stepped shape of the step portion.