A metal porous body is a metal porous body mainly composed of nickel and having a framework of a three-dimensional network structure, Ni(OH)2 being present in a surface of the framework, when the metal porous body is subjected to at least 30 potential scans between a lower limit potential of −0.10 V and an upper limit potential of +0.65 V with respect to a hydrogen standard potential in not less than 10% by mass and not more than 35% by mass of a potassium hydroxide aqueous solution, at least oxygen being detected within a depth of 5 nm from the surface, and hydrogen being detected at least in the surface.