The possibility of the loss of information stored in a memory cell which
is caused by repeating the reading action on the same memory cell
comprising a variable resistance element and a select transistor can
significantly be reduced. A voltage applying circuit for selecting one or
more of the memory cells from a memory cell array and applying voltages
to the word lines, bit lines, and source lines for programming, erasing,
and reading information applies a voltage between the bit line and the
source line connected to the selected memory cell so that the voltage
applied between the two ports of the variable resistance element in the
selected memory cell during the reading action is equal in the polarity
to one of the voltages applied between the two ports of the variable
resistance element for the programming action and the erasing action
respectively whichever is greater in the absolute value.