1. A search device comprising: circuitry configured to: extract partial character strings which are portions of an input character string; acquire position information and boundary information of an entry, corresponding to each of said partial character strings, for each name data from indexes which are generated in advance; determine continuity in said each name data between entries which are acquired on a basis of said position information such that the continuity is determined to exist when a travel distance between arbitrary partial character strings within a single word included in the input character string and a travel distance between entries within a single word in name data corresponding to said arbitrary partial character strings are equal to or shorter than predetermined distances, respectively; and add a maximum comparison score to one of said entries which is determined to be continuous to the other entry, and add a comparison score according to validity of continuity with each of entries placed before and after said entry which has been determined to be discontinuous to the other entry to said entry on a basis of said boundary information.