In a method of writing into a nonvolatile semiconductor memory device
including a resistance memory element which memorizes a high resistance
state and a low resistance state and switches between the high resistance
state and the low resistance state by an application of a voltage, a
variable resistor is parallelly connected to the resistance memory
element, and when the voltage is applied to the resistance memory element
to switch the resistance memory element between the high resistance state
and the low resistance state, a resistance value of the variable resistor
is set corresponding to the resistance state of the resistance memory
element so that a writing circuit for applying the voltage to the
resistance memory element, and a synthetic resistor of the resistance
memory element and the variable resistor make the impedance-matching.