Resistive random access memory (RRAM) devices are made by copper nitride films prepared by DC magnetron sputtering. After a forming process, the CuxN-based RRAM devices show bipolar character with low operation voltage and distinguishable resistance ratio. The fitting results for the electrical measurements and the conducting atomic force microscope (CAFM) analysis indicate that resistive switching mechanism is consistent with the formation and rupture of conducting filaments. Simultaneously, the distribution of conducting filaments measured by CAFM reveals a promising potential to fabricate high-density RRAM device by using this material. The mechanism of the formation of conducting filaments is discussed based on our results.