Provided is a binder for non-aqueous secondary battery porous membrane-use that enables formation of a porous membrane having excellent durability and that can improve stability under high shear of a composition for porous membrane-use. The binder for non-aqueous secondary battery porous membrane-use includes a particulate polymer. The particulate polymer is a random copolymer including at least 35 mass % of an alkyl (meth)acrylate monomer unit and at least 20 mass % and no greater than 65 mass % of an aromatic monovinyl monomer unit. A degree of swelling of the particulate polymer with respect to a non-aqueous electrolysis solution is greater than a factor of 1 and no greater than a factor of 2.