A semiconductor memory device includes a plurality of detecting code generators configured to generate a plurality of detecting codes to detect errors in a plurality of data items, respectively, a plurality of first correcting code generators configured to generate a plurality of first correcting codes to correct errors in a plurality of first data blocks, respectively, each of the first data blocks containing one of the data items and a corresponding detecting code, a second correcting code generators configured to generate a second correcting code to correct errors in a second data block, the second data block containing the first data blocks, and a semiconductor memory configured to nonvolatilely store the second data block, the first correcting codes, and the second correcting code.