A nonvolatile semiconductor device is configured so that a load circuit
applying voltage to a variable resistive element is provided electrically
connecting in series to the variable resistive element, a load resistive
characteristic of the load circuit can be switched between two different
characteristics. The two load resistive characteristics are selectively
switched depending on whether a resistive characteristic of the variable
resistive element transits from low resistance state to high resistance
state, or vice versa, voltage necessary for transition from one of the
two resistive characteristics to the other is applied by applying writing
voltage to a serial circuit of the variable resistive element and load
circuit. After the resistive characteristic of the variable resistive
element transits from one to the other, voltage applied to the variable
resistive element does not allow a resistive characteristic to return
from the other to one depending on the selected load resistive
characteristic.