A chain type ferroelectric random access memory has a memory cell unit
including ferroelectric memory cells electrically connected in series to
each other, a plate line connected to an electrode of the memory cell
unit, a bit line connected to the other electrode of the memory cell unit
via a switching transistor, a sense amplifier which amplifies the
voltages of this bit line and its complementary bit line, and a
transistor inserted between the switching transistor and the sense
amplifier. A value, being the minimum value of the gate voltage in the
transistor obtained during elevation of the plate line voltage and
comparative amplification, is smaller than a value, being the maximum
value of the gate voltage in the transistor obtained during fall of the
plate line voltage and comparative amplification. With these features,
decrease in the accumulated charge of polarization in the memory cell is
reduced and occurrence of disturb is prevented during read/write
operations.