A resistive random access memory is provided. The resistive random access memory includes a bottom electrode, a metal oxide layer including a plurality of conductive filament regions formed on the bottom electrode, and a plurality of top electrodes formed on the metal oxide layer, corresponding to the respective conductive filament regions. Each of the conductive filament regions has a bottom portion and a top portion. The width of the bottom portion is greater than that of the top portion. The conductive filament regions include oxygen vacancies, and regions other than the conductive filament regions in the metal oxide layer are nitrogen-containing regions.