The present invention provides a separator for a non-aqueous secondary battery including a porous substrate and an adhesive layer that is formed on one side or both sides of the porous substrate and is an aggregate layer of particles that include a polyvinylidene fluoride resin, the adhesive layer further including a filler that includes at least one of an organic compound or an inorganic compound, the content of the filler being from 20% by mass to 80% by mass, with respect to the total mass of the mass of the particles and the mass of the filler, and the content of the particles per one adhesive layer being from 0.1 g/m2 to 6.0 g/m2.