A method for preparing a metal foam is provided which can freely control characteristics, such as pore size and porosity, of the metal foam, prepare the metal foam in the form of films or sheets which have conventionally been difficult to produce, particularly the form of thin films or sheets as well, and prepare a metal foam having excellent other physical properties such as mechanical strength. It is also possible to efficiently form a structure in which the metal foams as above are integrated with good adhesive force on a metal base material.