An embodiment of the present invention provides a video signal multiplexing apparatus including a separator separating picture information and additional information from a received video signal, a controller adjusting, if the picture information is out of sync with the additional information, a data amount of the additional information based on a data amount of the picture information in such a manner that the picture information is in sync with the additional information, and a multiplexer multiplexing the encoded data and the additional information the data amount of which has been adjusted.