SEPARATOR FOR LEAD ACID STORAGE BATTERIES, AND LEAD ACID STORAGE BATTERY

A separator is disposed between a positive electrode and a negative electrode in a lead acid storage battery including the positive electrode and the negative electrode, in which the separator contains a glass fiber and an organic binder, the separator includes a first layer that is in contact with the positive electrode, and a second layer that is in contact with the negative electrode, an average pore diameter of the first layer is larger than an average pore diameter of the second layer and a thickness of the first layer is equal to or less than the half of the overall thickness of the separator