A speech dialogue control method of a speech dialogue system where connection is made to a voice input device that inputs user voice, the method comprising: receiving first instruction information, representing a first instruction content as to the speech dialogue system, from the voice input device; extracting, in a case of having received the first instruction information from the voice input device, first voice information, indicating a voice feature value of the user who has input the first instruction information, contained in the first instruction information, and recognizing a first instruction content which the first instruction information represents; performing instruction request notification, in a case where the recognition result of the first instruction content is that processing to be executed could not be uniquely identified based on the first instruction content, thereby prompting the user to input information necessary for uniquely identifying the processing; extracting, in a case where utterance information which is voice uttered by the user is received from the voice input device after the instruction request notification, second voice information included in the utterance information, indicating a voice feature value of the user who has input the utterance information, and determining whether or not the first voice information and the second voice information that have been extracted match; and in a case where determination is made that the first voice information and the second voice information do not match, executing processing to make notification to the effect that input of the utterance information cannot be accepted, or not executing processing identified based on the first instruction content and the voice information that have been input. receiving first instruction information, representing a first instruction content as to the speech dialogue system, from the voice input device; extracting, in a case of having received the first instruction information from the voice input device, first voice information, indicating a voice feature value of the user who has input the first instruction information, contained in the first instruction information, and recognizing a first instruction content which the first instruction information represents; performing instruction request notification, in a case where the recognition result of the first instruction content is that processing to be executed could not be uniquely identified based on the first instruction content, thereby prompting the user to input information necessary for uniquely identifying the processing; extracting, in a case where utterance information which is voice uttered by the user is received from the voice input device after the instruction request notification, second voice information included in the utterance information, indicating a voice feature value of the user who has input the utterance information, and determining whether or not the first voice information and the second voice information that have been extracted match; and in a case where determination is made that the first voice information and the second voice information do not match, executing processing to make notification to the effect that input of the utterance information cannot be accepted, or not executing processing identified based on the first instruction content and the voice information that have been input.