1. A server device comprising: a control unit collecting texts stored in a storage unit in response to a general word extracting request signal input by a user or when a predetermined time is reached, extracting words from said collected texts, determining, as a general word, a word which appears at a frequency higher than a first predefined value for a first predetermined period, and which appears at a frequency varying within a second predefined value range for every second predetermined period shorter than said first predetermined period, and creating a general word list which enumerates a plurality of general words including said general word, wherein said control unit, when a keyword for a search is entered, collects texts including said keyword from texts stored in said storage unit, extracts nouns from collected first texts, determines a noun which partially matches said keyword as a first word, extracts second texts including said first word from among said first texts, extracts a word which belongs to at least one word from among a noun, verb, and adjective from said second texts, counts a number of times said extracted word is used, determines words which are ranked at a predetermined position or higher with respect to the number of times said words are used, as second words which are pertinent word to said first word, lowers the rank of a second word which matches any one from among said plurality of general words in said general word list, and outputs said second words together with said first word.