Abstract: The present invention enables to preferably correct mark patterns reproduced in parallel from a magnetic tape. A mark detection block 204 successively identifies as one of the plurality mark patterns a plurality of binary data reproduced in parallel from the magnetic tape, and confirms a mark pattern whose reproduction time has reached a reference time. A mark holding block 211 holds a mark pattern whose reproduction is integrated. A mark pattern discontinuity detection block 121 detects a discontinuity and the discontinuity integrating block 213 counts the number of discontinuity times. This discontinuous number of times and the mark pattern held are output together with the confirmed mark pattern, thus correcting the mark pattern appropriately.