1. A next search keyword presentation apparatus, comprising: an input unit for inputting a search keyword; a search control unit which sends the search keyword to a search system and receives a search result from the search system in the form of a plurality of documents; a display unit which displays the documents of the search result; a text body extraction unit which extracts a text body from the plurality of search result documents, wherein the text body extraction unit removes a portion from the plurality of search result documents deemed unrelated to the text body; an analysis unit which carries out a semantic attribute analysis of words contained within the text body; a storage unit which stores the search keyword as user history data uniquely provided for each user; a creation unit which creates document representative information based on the semantic attributes of each word and the history data; and a cluster representative keyword extraction unit which clusters document characteristic information and extracts cluster representative keywords; wherein the display unit displays the cluster representative keywords as the next search keyword candidate in response to inputting the search keyword.