According to method of managing and reproducing additional audio files of an interactive optical disc, additional audio data associated with main video data of an optical disc such as an interactive DVD are recorded as a file of a prescribed format. File information about the additional audio data and buffering information thereabout recorded in the file of a prescribed format. An optical disc apparatus interprets the file information and buffering information and then carries out a series of operations storing and reading out and playing the additional audio data in a way suitable to the buffering area allocated within a buffer. Consequently, additional audio data of various contents are read out from the optical disc or provided by a content providing server connected through the Internet.