A resistive memory device and a method of operation of the resistive memory device are provided. The resistance memory device includes a resistance change layer that has a tunneling film and has many states. The conductance is changed symmetrically in a SET operation and a RESET operation. Thus, the resistive memory device can be used for efficient and accurate data storage as a RRAM in a high-capacity memory array, and as a synaptic device controlling the connection strength of a synapse in a neuromorphic system.