1. An electronic watermark embedment apparatus embedding information in image data, the electronic watermark embedment apparatus comprising a computer including: a detection device configured to detect a figure pattern area allowing an embedment of a figure pattern including a basic pattern and a directional pattern indicating a predetermined direction in relation to the basic pattern, the figure pattern expressing information to be embedded or a position of an area in which the information to be embedded exists, from an area other than a background within the image data; and an embedment device configured to generate image data embedded with a watermark by embedding the figure pattern on a character in the detected figure pattern area.