4. The decoding device according to claim 3 , wherein each of the N code streams is data generated by every partially symbol coding source data which is structured by arranging unit symbols consisting of N partial symbols in multiples, and a N code stream corresponding to the i stage decoder ranges from a top symbol of the unit symbols to i−1 of the partial symbol and comprise data that are decoded using probabilistic models set on the basis partial symbols from the top symbol of the unit symbols to i−1 among the multiple probabilistic models having the i stage decoder.
5. The decoding device according to claim 4 , wherein a first stage decoder among the N decoders generates the partial symbols using the predetermined probabilistic models which differ from the probabilistic models stored in a second stage and higher stages in the memory, and outputs the generated partial symbols.