The present invention provides an information recording medium in which an access unit including basic data and extension data is recorded, so as to allow a decoder that decodes only basic data to process the access unit which includes the basic data and the extension data for the next generation.The information recording medium is an information recording medium on which a stream is recorded, the stream having plural access units and including at least one of video and audio, wherein each of the access units has basic data and extension data related to the basic data, the basic data is data that can be decoded into a completed state without requiring the extension data, and the extension data is data for improving the quality of data generated from the basic data, and information indicating that the extension data is included in each of the access units is recorded in an area, included in the access unit, which cannot be identified by the decoder which decodes only the basic data.