The resistive switching random access memory (ReRAM) device using Ni/NiO nanowire as a building block was demonstrated; this is prepared by a combination of top-down and bottom-up techniques. The Ni nanowire arrays on Si substrates were prepared by electroplating of Ni into the anodic aluminum oxide (AAO) template, and the surface of the nanowires were oxidized by O2 plasma treatment at room temperature. We observed an improvement of stability of the switching properties in the nanowire device compared with the device using nickel oxide thin film.