This memory comprises a first frequency detecting portion detecting access frequencies with respect to a plurality of memory cell blocks respectively, a comparator comparing the access frequencies with respect to the plurality of memory cell blocks detected by the first frequency detecting portion with each other and a refresh portion exercising control for selecting a prescribed memory cell block from among the plurality of memory cell blocks on the basis of comparison data output from the comparator and preferentially rewriting data in the memory cells included in the selected memory cell block.