A technique is provided for automatically and visually generating a display rule for a structured document based on an exemplary operation. Base display rule generation means 21 generates a first display rule 29, which is a base, by using a document type definition 27 for a structured document 26 and a default generation rule 28 that is determined in advance. Display document generation means 22 employs the first display rule 29 and the structured document 26 to generate a first display document 30 and an element correlation file 31. Tie first display document 30 is edited in a display document visual editing environment 23, and a second display document 32 and an editing operation history file 33 are generated. Display rule updating means 24 refers to the second display document 32, the editing operation history file 33, the element correlation file 31 and the structured document 26 to generate a second display rule 34 that reflects the editing contents.