disclosed is an iterative decoding method using a soft decision output viterbi algorithm for block turbo codes using product codes wherein block codes are concatenated by greater than three dimensions , which comprises : a transmitter configuring a product code of greater than three dimensions and transmitting it ; 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 sequentially iterating the soft decision output viterbi algorithm decoding with respect to the respective axes .