Migration of atoms is presented to be utilized for fabrication of metallic micro/nanomaterials by controlling the phenomenon. Two kinds of migration phenomena are treated; one is electromigration and the other is stress migration. In addition to the formation of micro/nanomaterials, some achievements in enhancing their functions are demonstrated. One is a technique to fabricate nanocoils from the formed Cu nanowires. The others are techniques to weld or cut the micro/nanowires by using Joule heating. Finally, regarding evaluation of mechanical and electrical properties of the micro/nanomaterials, the concentrated-mass cantilever technique in atomic force acoustic microscopy and the four-point atomic force microscope technique are shown to be powerful tools, respectively.