The present invention provides a file structure analyzing apparatus for analyzing a file including a group of structured data formed into a tree structure by having a plurality of distinct element packets referenced externally, each of the distinct element packets including a unique identifier for identifying the distinct element packet in question and an external referrer for indicating an external reference destination at which to reference externally another distinct element packet using the unique identifier of the latter packet, the file structure analyzing apparatus including: a distinct element packet input section; an external referrer holding section; a unique identifier holding section; and a reference relationship analysis section.