A digital watermark embedding device uses frame correlation to perform motion detection on an input temporally sequential video signal. Based on detected motion information, when a picture is moving at such a speed that a stationary pattern cannot be visually perceived, the device controls a digital watermark pattern to be stationary, while, when a picture is moving at such a speed that a stationary pattern can be visually perceived, the device moves the digital watermark pattern to follow the motion. This makes it possible to effectively superimpose a digital watermark pattern on the input video signal.