An efficient encoding method for error correction coding for recording/reproducing information in a high-density magnetic recording/reproduction apparatus. Based upon the principle of Turbo coding for random error-correction a practical encoding method is provided for preventing the propagation of code errors from being caused by the failure of the error correction due to burst signal errors existing on actual reproduced signal and recovering reliable code data from this. An information code sequence is divided in units of code block and the random error-correction coding is applied to an individual code block. Concatenated coding with hard-decision error-correction code for compensating a burst error is subsequently applied. This allows the encoding method to reduce the decoding time delay, or latency, in iterative decoding for the error-correction thereby achieving high-speed error correction.