1. A keyword presenting device comprising: an extraction unit configured to extract a plurality of keywords from a browsing document; a determination unit configured to arrange keywords, of the plurality of keywords, with spellings similar to each other to obtain a plurality of groups of similar keywords; an integration unit configured to classify keywords of each of the plurality of groups into a main keyword that is a title and at least one sub-keyword, and to associate the main keyword with the sub-keywords for each of the plurality of groups; and a presentation unit configured to present the main keywords of respective groups of the plurality of groups, wherein the presentation unit is further configured to, in response to one of the main keywords being selected by a user, allow selection of a sub-keyword, with a spelling similar to the one of the main keywords, of the at least one sub-keyword associated with the one of the main keywords.