1. A related word presentation device which generates association dictionaries, each association dictionary including words and degrees of relevance between the words, the related word presentation device comprising: a computer configured to operate as: a program information storage unit in which program information is stored, the program information being information indicating, for each program among programs contents of each program using words; a classifying unit configured to generate groups for each attribute among attributes of the words included in the program information, each of the groups being made for a reference word, each reference word being among reference words included in each attribute, each of the groups including (i) a corresponding one of the reference words and (ii) a set of words which co-occur with the corresponding one of the reference words in the program information including the corresponding one of the reference words; a first degree-of-relevance calculating unit configured to store the association dictionaries for the respective attributes, the association dictionaries each including (i) a possible pair of words in the groups of a corresponding one of the attributes of the words and (ii) the degree of relevance between the words in the possible pair, a value of the degree of relevance becoming greater with an increase in the number of the groups of the corresponding one of the attributes of the words including the possible pair of words in a same group; an obtaining unit configured to obtain a search word and an attribute of the search word; a first related word selecting unit configured to select, as a first related word, a word related to the search word obtained by the obtaining unit from a corresponding association dictionary for the attribute obtained by the obtaining unit from among the association dictionaries for the respective attributes; and a presenting unit configured to present the first related word selected by the first related word selecting unit.