14. The specific call detecting method according to claim 13 , wherein the determining whether at least one of the first and second voices is to be a target of voice recognition or not, determines that the first voice is a target of voice recognition until a period in which the utterance ratio is higher than a predetermined threshold, reaches a first period, and determines that the first voice is not a target of voice recognition after the period in which the utterance ratio is higher than the threshold, reaches the first period.
20. The specific call detecting method according to claim 14 , further comprising determining whether the psychological state of the first speaker is normal or not on the basis of the first voice, wherein the detecting a keyword related to a specific call, calculates the degree of similarity between the voice determined as the target of the voice recognition and the keyword, detects the keyword when the degree of similarity is equal to or higher than a similarity threshold, and sets the value of the similarity threshold when it is determined that the psychological state of the first speaker is not normal to be smaller than the value of the similarity threshold when it is determined that the psychological state of the first speaker is normal.