To improve the penetration short-circuit resistance of a valve-regulated lead-acid battery. A mixed and scooped mat of glass fibers and organic fibers is used as a separator 3 of a battery comprising an electrode plate pack 4 obtained by inserting the separator 3 between a positive electrode plate 2 and a negative electrode plate 1 and housed in a container 5 and an electrolyte retained in the electrode plate pack 4 and the separator 3, wherein the separator is a mixed and scooped mat of glass fibers and organic fibers and the electrolyte is silica sol mixed with silica and silica sol is injected as the electrolyte.