An electrode assembly includes a cell stack part having (a) a structure in which one kind of radical unit is repeatedly disposed and has same number of electrodes and separators which are alternately disposed and integrally combined, or (b) a structure in which at least two kinds of radical units are disposed in a predetermined order, and an auxiliary unit disposed on at least one among an uppermost part or a lowermost part of the cell stack part. The one kind of radical unit of (a) has a four-layered structure in which a first electrode, a first separator, a second electrode and a second separator are sequentially stacked or a repeating structure in which the four-layered structure is repeatedly stacked, and each of the at least two kinds of radical units are stacked by ones in the predetermined order to form the four-layered structure or the repeating structure.