A purchase settlement method is provided. Voice information is acquired. A spoken command indicating a control instruction as to a device is obtained based on the acquired voice information. When the spoken command relates to purchase settlement, speaker information relating to a speaker who has spoken the acquired voice information is identified based on the acquired voice information. It is determined whether or not the identified speaker information is of a speaker permitted to perform purchase settlement by referencing a table in which speaker information of speakers permitted to perform purchase settlement and information necessary for purchase settlement are associated with each other. When it is determined that the identified speaker information is of the speaker permitted to perform purchase settlement, purchase settlement processing is performed using the spoken command and the information necessary for purchase settlement.