In one embodiment, a symbol error correction encoder effects block
interleaving on recording data and thereafter performs first error
correction encoding on the recording data. Next, a symbol error
correction encoder performs encoding on the whole block. A reproducing
processing circuit outputs likelihood information of respective bits. A
first error correction decoder corrects a random error produced upon
recording and reproduction, using the likelihood information. Since it is
possible to make an improvement in performance with respect to the random
error by repetitive decoding at this time, the post-correction data is
returned to the reproducing processing circuit. After the completion of
such repetitive processing, the data is digitized and subjected to an
error correction in symbol unit by a hard determination, and outputted to
a symbol error correction decoder.