8. A corpus generation method for generating accurate corpus data of presentation targets for use in a search operation for the presentation targets, the corpus generation method comprising: a web page acquisition step of acquiring a web page including description sentence data regarding a presentation target; a reference word acquisition step of acquiring a reference word that is an attribute value regarding the presentation target from the web page; an attachment step of extracting an broader word belonging to a layer above the reference word acquired in the reference word acquisition step from a storage that stores hierarchical relationship information indicating a hierarchical relationship between attribute values, and attaching an attribute tag, indicating an attribute name, corresponding to the reference word to the broader word included in the description sentence data when the broader word is included in the description sentence data; an output step of outputting, as corpus data, the description sentence data to which the attribute tag is attached in the attachment step; and a storing step of storing, in a presentation target information registration storage, a set of the attribute name and the attribute value regarding the presentation target acquired from the corpus data output, in the output step, in association with the web page, wherein, when a search for the presentation target is requested, the presentation target is searched by referring to the presentation target information registration storage based on the attribute name and the attribute value regarding the presentation target.
9. The corpus generation method of claim 8 , wherein the web page acquisition step comprises receiving the web page from a server.