PURPOSE: To eliminate pole plates coming into contact with each other even if winding shift occurs in a group of pole plates and thereby eliminating short- circuiting and reduce defective rate remarkably by providing separators which are sufficiently higher than the pole plates.

CONSTITUTION: With regard to the difference between a separator 5 lengthwise width and a positive electrode plate 6 lengthwise width when the lengthwise width of the separator 5 is equal to or more than the lengthwise width of a pole plate 6, if there is too much difference, a harmful effect occurs at a winding work and workability is impaired. Also, if the difference is too little, the pole plate 6 is exposed from the separator 5 and there is fear of short-circuiting. Accordingly, a separator lengthwise width is generally made (X+α)mm against the positive electrode plate height Xm, but α=2-5mm. That is, in the case of making a positive electrode plate height Xmm, a separator width is made X+2-3mm in a fold portion direction and X+4-5mm in an opening direction (the end side of the winding).