1. A digital watermark embedding method in a digital watermark embedding apparatus for embedding digital watermark into moving images, comprising: a step of inputting moving image data including a frame image group, watermark information and watermark pattern switching information specifying temporal change of watermark patterns; a frame image obtaining step of sequentially obtaining, by frame image obtaining means, each frame image of the moving image data and frame display time that is display time of the frame image; a watermark pattern generation step of generating, by watermark pattern generation means, a watermark pattern using the watermark information, the frame display time and watermark pattern switching information; a watermark pattern superimposing step of superimposing, by watermark pattern superimposing means, the watermark pattern onto the frame image; and a moving image data reconstruction step of combining watermark embedded frame images obtained by sequentially repeating processes of the frame image obtaining means, processes of the watermark pattern generation means and processes of the watermark pattern superimposing means to generate watermark embedded moving image data.