An apparatus is designed for using a music content composed of at least one content material in accordance with security information of the music content. In the apparatus, a reading section reads a recording medium which records a data file of the music content having a chunk structure including a content material chunk and a security information chunk. The content material chunk contains substantial data of the content material and identification information for uniquely identifying the content material. The security information chunk contains security information of the content material and identification information for uniquely identifying the content material. A using section permits use of the content material when the identification information read from the content material chunk coincides with the other identification information read from the security information chunk.