An electrode assembly in which a positive electrode and a negative electrode are alternately stacked, and a separator is disposed between the positive and negative electrodes comprises: a folding unit, a negative electrode unit, and a positive electrode unit alternately inserted between layers of the separator of which one side and the other side are alternately folded in a zigzag shape in a direction perpendicular to a direction in which the positive electrode and the negative electrode are stacked; and a stacking unit in which the positive electrode, the separator, and the negative electrode, each of which is cut by a predetermined size, are sequentially stacked. The folding unit having a Z-folding structure and the stacking unit having a lamination & stacking structure may be bonded to each other. Thus, the positive electrode may increase in area relative to the negative electrode in the folding unit to increase in capacity.