To provide a plate group of high quality with a simple structure, while surely preventing the generation of stress concentration due to a protecting tape arranged on a collector at the time of winding.

A tip side peripheral surface 14a of a winding shaft 14 is provided with a level difference part 22 which extends in the axial direction, in response to the length of a protecting tape 9 arranged on a collector 7 as a structural member of a positive plate 4. Since the protective tape part 9 formed thicker than other parts is housed in the level difference part 22, the generation of stress concentration due to the thickness of the protecting tape 9 at winding by the winding shaft 14 can be prevented as much as possible.