LEAD STORAGE BATTERY SEPARATOR AND LEAD STORAGE BATTERY

[Problem] To provide a separator for a flooded lead acid battery that is optimum for idle stop vehicles.[Solution] A separator for a flooded lead acid battery, including a porous film containing a polyolefin resin and inorganic powder as major materials, having ribs disposed on both surfaces of the porous film; having a locational relationship of the ribs on the both surfaces that is arbitrarily determined; assuming that one of the both surfaces that has the ribs having a lower average height disposed thereon is a negative electrode side, having linear ribs in a vertical direction provided on the negative electrode side; and on application of a pressure of 10 kPa to flat plates that sandwiched the porous film from both surfaces thereof, having a space of 0.02 mm or more between a back web surface of the negative electrode side and the flat plate.