This invention is directed to a recording medium on which contents data of movie, etc. is recorded. At the position where reproduction is carried out prior to first data consisting of contents data in reproducing the first data, there is recorded second data like advertisement data in which contents concealment data for concealing contents data is buried. In reproduction of the first data recorded on this recording medium, contents concealment data is extracted from the second data, and cipher implemented to the first data which has been read out from the recording medium is decoded by using the extracted contents concealment data. Thus, the first data is reproduced subsequently to the second data.