To provide an enclosed lead acid storage battery in which the internal short circuit at the bottom part of the electrode plate is prevented and the designed cycle life is not shortened.

The reinforcing retainer 4 of a nearly U shape which reinforces the bending portion of the retainer 3 is stuck to the positive electrode plate 1 so as to envelop the bottom end of the positive electrode plate 1 and the positive electrode plate 1 which is stuck with this reinforcing retainer 4 is enveloped by the retainer 3. The bending portion 3a of the retainer 3 is doubled with the reinforcing retainer 4 and the retainer 3, and reinforced by the reinforcing retainer 4.