A metal adsorbent which can adsorb a wide variety of metals, can conform to various uses, and adsorbs metals in large amounts. Metal adsorbents in various forms, which have the property of highly efficiently adsorbing metals, are produced by (a) a method in which a polyamine polymer is chemically bonded and immobilized to a porous support, (b) a method in which a polyamine polymer is blended into a solution of a raw material for fibers and the mixture is formed into fibers by wet-spinning or dry spinning, and (c) a method in which a polyamine polymer is blended into a solution of a film-forming polymer and the mixture is formed into a film by a method of film formation from solution.