A metallic porous body having skeleton forming the three-dimensional network structure, the overall shape is flat, the framework has a hollow structure, and a main metal layer, a first microporous layer and the second are those comprising at least one microporous layer, said main metal layer is composed of nickel or a nickel alloy, wherein the first microporous layer comprises nickel and chromium, of the main metal layer is intended to be formed on the outer peripheral surface side, the second microporous layer comprising nickel and chromium, intended to be formed on the inner peripheral surface side of the main metal layer opposite the hollow space of the skeleton there, the porous metal body.