1. An electronic watermark editor of a compressed video with an electronic watermark that expresses information by a relative difference between two DCT coefficient values, comprising: a means for specifying a template to instruct on a block position used for a video when embedding an electronic watermark; and a smoothing means for smoothing a relative difference between a pair of DCT coefficient values of a block instructed by the template, wherein the electronic watermarks are deleted by the smoothing means.