An object of this invention is to provide a data structure description method and processing method, which can present the contents of data to the user in every devices as much as possible. A data processing method of this invention has a parsing step of parsing a structured document having second data which is included in first data described in a first markup language, is described in a second markup language, and is required to present contents corresponding to the first data, and a processing step of executing, if it is determined in a determination step that a part described in the first markup language of the parsed structured document cannot be understood, a process of data on the basis of a part described in the second markup language.