NON-AQUEOUS SECONDARY BATTERY SEPARATOR AND NON-AQUEOUS SECONDARY BATTERY

An embodiment of the invention provide a separator for a non-aqueous secondary battery, including a porous substrate; and a heat-resistant porous layer that is provided on one side or on both sides of the porous substrate, and that contains a binder resin and barium sulfate particles, in which an average primary particle diameter of the barium sulfate particles contained in the heat-resistant porous layer is from 0.01 µm to less than 0.30 µm, and in which a volume ratio of the barium sulfate particles in the heat-resistant porous layer is from 30% by volume to less than 50% by volume.