1. A digital watermark embedding device comprising: an embedding-information converting unit for converting inputted information to be embedded into a bit string formed of “0's” and “1's” and embedding respective bits of the converted bit string multiple times to output a digital watermark pattern having N −1's or N+1's as elements; an orthogonal-pattern generating unit for generating orthogonal patterns each formed of a combination of elements of −1's and +1's and orthogonal to one another; an integrating unit for integrating each of the orthogonal patterns from the orthogonal-pattern generating unit with each of the elements of the digital watermark pattern from the embedding-information converting unit to generate an embedding pattern; and a digital-watermark embedding unit for embedding pattern from the integrating unit in an input image and outputting an image after embedding information.