Encoding and decoding devices and methods are provided. All the components of LH, HL, HH sub-band coefficients of the same hierarchy and the same space coordinate are extracted as a set from a wavelet sub-band space. Furthermore, it is judged whether each component of each coefficient is zero and as 1-bit judgment result, the respective judgment results are combined to obtain multi-bit flag information. Upon encoding, firstly, the Huffman information is subjected to variable-length encoding by the Huffman encoding code. After this, only the coefficient values which are not zero are similarly subjected to the variable-length encoding by the Huffman code or the like and outputted.