Disclosed is an iterative decoding method using a soft decision output Viterbi algorithm (SOVA) for block turbo codes using product codes wherein block codes are concatenated by greater than three dimensions, which comprises: (a) a transmitter configuring a product code of greater than three dimensions and transmitting it; (b) configuring the signal transmitted by the transmitter into frames for decoding, and initializing external reliability information respectively corresponding to an axis corresponding to the product code of greater than three dimensions; and (c) sequentially iterating the soft decision output Viterbi algorithm (SOVA) decoding with respect to the respective axes.