A digital watermark embedding apparatus comprises below units. A first
generation unit generates a plurality of symbol sequences each of which
includes a plurality of symbols including ranks, each of the ranks being
uniquely numbered among each of the symbol sequences, each of the symbol
sequences uniquely corresponding to each of a plurality of identification
information items to be embedded as digital watermark information into
each of copies of digital contents. A second generation generates a
plurality of to-be-embedded codes corresponding to each of the symbols in
each of the symbol sequences. An embedding unit embeds the to-be-embedded
codes in each of the copies.