A moving picture coding and/or decoding system includes a encoder (10) for coding input image data, a divider (14) for dividing a code string supplied from the encoder, (10) into a plurality of code strings, a reorder (15) for arranging at least one of the plurality of code strings in the forward direction from the head to the end, and at least one of the other code strings in the backward direction from the head to the end. A variable-length coding system includes a code-word table for storing a plurality of code words so that the code words correspond to source symbols, and an encoder for selecting a code word corresponding to the source symbol inputted from the code-word table and for outputting the selected code word as coding data. The plurality of code words can be decoded in either of the forward and backward directions. The plurality of code words are configured so that the pause between codes can be detected by a predetermined weight of the code word (in the case of a binary code, the number of "1" or "0" in the code word).