1. An intent understanding device, comprising: a voice recognizer that recognizes one speech spoken in a natural language by a user, to thereby generate plural voice recognition results of highly ranked recognition scores; a morphological analyzer that converts the respective voice recognition results into morpheme strings; an intent understanding processor that estimates an intent about the speech by the user on the basis of each of the morpheme strings, to thereby output from each one of the morpheme strings, one or more candidates of intent understanding result and scores indicative of degrees of likelihood of the candidates and generate the candidates of intent understanding result in descending order of likelihoods of the plural voice recognition results; a weight calculator that calculates respective weights for the candidates of intent understanding result using setting information previously set by a user of a control target apparatus that operates based on the intent understanding result selected by the intent understanding corrector; and an intent understanding corrector that corrects the scores of the candidates of intent understanding result, using the weights, to thereby calculate their final scores, and then selects the candidate of intent understanding result with the final score that satisfies a preset condition first, as the intent understanding result, wherein the weight calculator has a table in which constrained conditions and the weights to be used when the respective constrained conditions are satisfied, are defined, and determines whether or not the constrained condition is satisfied, based on the setting information previously set by the user of the control target apparatus, to thereby select each of the weights.