Abstract: In order to improve the anticorrosion properties of a flat plate or an intake/outlet passage plate provided at an outermost end in the direction of lamination in a laminated heat exchanger, a sacrificial layer, whose electrical potential is lower than the electrical potential of the core material, is provided at the outer surface of the flat plate or the intake/outlet passage plate located at the outermost end of the laminated heat exchanger in the direction of lamination. The above arrangement prevents corrosion of the core material through sacrificial corrosion of the sacrificial layer.