A digital watermark embedding method of the present invention includes: a step of sequentially obtaining each frame image of the moving image data and frame display time; a step of generating a watermark pattern using watermark information, the frame display time and watermark pattern switching information; a step of superimposing the watermark pattern onto the frame image, and combining watermark embedded frame images obtained by sequentially repeating the processes to generate watermark embedded moving image data. A digital watermark detection method includes a step of sequentially obtaining a frame image; a step of generating a difference image between the currently obtained frame image and a previously obtained frame image; and a step of performing digital watermark detection from the difference image to output digital watermark detection status, and when digital watermark detection process is continued, obtaining a new frame again to repeat the above processes.