A method and an apparatus for producing a microporous metal foil comprising (a) passing a metal foil through a gap between a pattern roll having large numbers of high-hardness, fine particles on the surface and a hard roll while pressing, to provide the metal foil with large numbers of fine penetrating pores, with a thin hard plastic film interposed between the metal foil and the pattern roll, and a thick soft plastic film interposed between the metal foil and the hard roll; and (b) adjusting tension applied to each of the metal foil, the hard plastic film and the soft plastic film to such an equal level that the metal foil is not broken during forming the fine penetrating pores.