PURPOSE: To obtain the coded data decoding method and its device by which the parallel performance of decoding processing is enhanced for the coded data cannot be decoded on the way of coding for high speed decode processing, and to decode at high speed.

CONSTITUTION: A 1st code area 36, that is, coded data is subject to Huffman decoding from its head in a decoding processing section 31 by a 1st processor and a 2nd code area 46, that is, coded data is subject to Huffman decoding on the way of coded data in a decoding processing section 41 by a 2nd processor. When any contradiction takes place in decoded data 52 decoded on the way of coding, decoding processing is started again from a new position. When the decoding processing of the 1st processor reaches the 2nd code area 46, the correct solution part of the decoded data 52 of the 2nd processor is adopted for the decoding result.