To provide a system for processing a structured document that can reduce labor for programming, in a software program for handling a structured document, by eliminating data conversion processing for processing of document contents and data extraction processing for selection of necessary data.

A structured document holds a document structure definition represented by declarations of document elements forming document contents and by a set of semantic relations defined between the document elements, and a set of instances of the respective document elements matching the document structure definition. The system for processing a structured document, which comprises data reading means for reading the instances of document elements from the structured document and editing them into data processible by a software program to provide them, comprises basic data structure selecting means for selecting and specifying a data structure of the data provided by the data reading means, from known basic data structures or object structures, such as array, set, list, tree, graph and table structures.