To provide an apparatus and method for realizing electronic watermark display for preventing illegal copy production by means of photographing an image again.

A long wavelength red light beam or a short wavelength blue light beam, concretely a red light beam with a wavelength of 650 to 700 nanometers or a blue light beam with a wavelength of 400 to 430 nanometers is adopted to display electronic watermark information on a screen or a display apparatus. Through the configuration above, it is possible that the electronic watermark information is hardly recognized by ordinary naked eyes but a photographed image by a video camera contains the electronic watermark resulting in deciding the validity of contents by means of detecting electronic watermark information from the photographed image such as whether or not the contents are those produced by rephotographing, and resulting in tracing a contents delivery path or the like.