Generation of a search query to be issued to a document search engine is supported by providing a GUI creation unit that generates a graphical user interface for supporting generation of a search query. The GUI creation unit generates a query-node creation window that is a GUI window for generating a new search word to be connected to a search query by a logical operator. The query-node creation window includes a sample-document preview area that displays a sample document, a facet list area that displays facets extracted from the sample document in list form, a query-node creation assist area to assist generation of the new search word, and a logical-operator selection icon to select a logical operator that connects the generated search word.