Disclosed is an electrode for a lithium-ion secondary battery which includes a porous membrane layer that is inhibited from decreasing in flexibility. The electrode for lithium-ion secondary battery comprises a current collector and, formed thereon in the following order, an electrode active-material layer comprising an electrode active material, a thickener, and a binder and a porous membrane layer containing an inorganic filler, wherein the binder is one which, when used to form a composite film comprising the binder and the thickener, forms a spherical island phase in a cross section of the composite film, the island phase having an average diameter of 0.5 μm or larger. The binder preferably is an unsaturated carboxylic acid ester polymer having a content of alkyl acrylate monomer units of 85 mass % or higher.