Resistance state can be controlled not only by sweeping voltages but also by applying voltage pulses. Figure 3 shows electric-field-induced resistance switching characteristics when voltage pulses were applied. During measuring, switching voltage to switch to the low resistance state was set at -80V and reset voltage to switch to the high resistance state was +80V where the voltage pulse with the pulse width of 100ms was applied five times, followed by applying -10V; this is how resistance values were obtained. Figure 3 shows the possibility of reversibly switching the resistance state by applying voltage pulses with different polarities, and a large amount of stable resistance change about two digits. Figure 3 does not show but an intermediate resistance state between the high resistance state and the low resistance state can be achieved by changing applying voltages for setting and resetting, the number of applying voltage, and pulse widths. These characteristics are also reported regarding thin film ReRAM devices, and are expected to improve memory density through multivalued systems.