The polymer electrolyte composite, for driving an electrolytic capacitor, according to the present invention is a composite body comprising an electrolyte and an acrylic polymer containing a copolymer of acrylic derivative. The electrolyte comprises a polar solvent and a solute comprising at least one of inorganic acids, organic acids and salts of such acids. The copolymer of acrylic derivative is a polymer of: a first monomer of at least one of a group of monofunctional monomers of acrylic derivatives each having at least one hydroxyl group at a terminal thereof and a polymerizable unsaturated double bond; and a second monomer of at least one of a group of multifunctional monomers of acrylic derivatives each having plural polymerizable unsaturated double bonds. The polymer electrolyte composite has a high ionic conductivity at room temperature together with a high heat resistance, and does not react with electrode foils such as aluminum, and moreover is superior in the easiness of manufacturing and long life. The present invention also provides an electrolytic capacitor using the polymer electrolyte composite.