A transmission method for enabling transmission of content using a broadcast wave and a communication channel, the content including first content data and second content data, wherein the transmission method comprises: transmitting auxiliary information using at least the broadcast wave; transmitting the first content data using the broadcast wave; transmitting the second content data using the communication channel; wherein the auxiliary information is information for causing a reception side to perform synchronization of the first content data and the second content data; the communication channel is different from broadcast; and the auxiliary information includes (i) attribute information indicating a relation between the first content data and the second content data; characterized in that the auxiliary information includes difference information between a reference clock of the second content data transmitted using the communication channel and a reference clock of the first content data transmitted using the broadcast wave, the difference information being used to achieve the synchronization through synchronization of said reference clocks; the auxiliary information further includes (ii) location information that indicates an acquisition destination of the content or information indicating an acquisition destination of the location information; and the video data and/or the audio data of the content is transmitted by the combination of the first content data and the second content data; the auxiliary information also includes information indicating a format of meta-information on playback control of the second content data transmitted using the communication channel; and the first content data is video data of the content and the second content data is audio data of the content; or video data or audio data is given by the combination of the first content data and the second content data. transmitting auxiliary information using at least the broadcast wave; transmitting the first content data using the broadcast wave; transmitting the second content data using the communication channel; wherein the auxiliary information is information for causing a reception side to perform synchronization of the first content data and the second content data; the communication channel is different from broadcast; and the auxiliary information includes (i) attribute information indicating a relation between the first content data and the second content data; characterized in that the auxiliary information includes difference information between a reference clock of the second content data transmitted using the communication channel and a reference clock of the first content data transmitted using the broadcast wave, the difference information being used to achieve the synchronization through synchronization of said reference clocks; the auxiliary information further includes (ii) location information that indicates an acquisition destination of the content or information indicating an acquisition destination of the location information; and the video data and/or the audio data of the content is transmitted by the combination of the first content data and the second content data; the auxiliary information also includes information indicating a format of meta-information on playback control of the second content data transmitted using the communication channel; and the first content data is video data of the content and the second content data is audio data of the content; or video data or audio data is given by the combination of the first content data and the second content data. <EOS>