An integrated composite-type separator sheet for use in a sealed type lead acid storage battery comprising: (i) at least one pressed fiber layer of a first type consisting essentially of glass fibers having an average diameter of 0.1-2 .mu., and (ii) a pressed fiber layer of a second type consisting essentially of glass fibers having an average diameter of 3-10 .mu., said pressed fiber layer of the second type having a thickness at least equal to the thickness of the pressed fiber layer of the first type.The separator and battery of this invention have the following advantages: good close contact between the separator and the electrode plates maintained for a long time during the use of the battery, and greatly improved performance of the battery and its service life, as compared with conventional batteries.