5. The document conversion apparatus of claim 4 , wherein the acquiring unit acquires, from a schema definition defining a structure of the structured document, the first data type corresponding to the first document element and the second data type corresponding to the second document element.
5. The document conversion apparatus of claim 4 , wherein the acquiring unit acquires, from a schema definition defining a structure of the structured document, the first data type corresponding to the first document element and the second data type corresponding to the second document element. 6. The document conversion apparatus of claim 5 , wherein the schema definition is described in an XML schema language.