Apparatus and method for transmitting watermark robust to acoustic channel distortion

Disclosed are an apparatus and a method for transmitting a watermark, robust to sound channel distortion. The method for transmitting a watermark includes the following steps: extracting a watermark from a first audio signal including watermarks; changing the watermark extracted according to a state of an audio channel; and outputting a second audio signal by inserting the changed watermark to the first audio signal.