A data memory device is provided that is capable of reading data accurately even if the reading action is repeated. Respective output ends of memory cells D0-D7 and input ends on one side of respective exclusive OR elements Eo0-Eo7 are interconnected, and the output end of a polarity holding cell Dc and the input ends on the other side of the respective exclusive OR elements Eo0-Eo7 are interconnected. When it is assumed that the stored value of the memory cell D0 is a logic “1” and the stored value of the polarity holding cell Dc is a logic “0,” the value of the output data Do0 read out becomes a logic “1”. By the reversal writing action that follows, the value of the memory cell D0 becomes a logic “0” and the stored value of the polarity holding cell Dc becomes a logic “1.” When the value of the memory cell D0 is read again in that state, the value of the output data Do0 is still a logic “1.” That is to say, even if data reading action is repeated, values of the output data Do0-Do7 remain unchanged. However, the direction of polarization of respective ferroelectric capacitors constituting the memory cells D0-D7 and the polarity holding cell Dc are reversed every time of the reading.