A data transmission device embeds information about a specific image into section information that is transmitted repeatedly at a time interval shorter than a time interval at which data broadcast contents are transmitted. In addition, the section information into which the specific information has been embedded, the data broadcast contents, and broadcast contents are multiplexed with each other. The multiplexed data is then transmitted to a data receiving device. The data receiving device detects that the output of the specific image included in the broadcast contents has been avoided and, if detected, searches for the specific information embedded in the section information and outputs the searched specific information to an output unit.