A dialogue device of a dialogue system relating to provision of a response to an inquiry from a user terminal includes an input unit that acquires the inquiry from the user terminal, a transmission unit that connects the user terminal and an operator terminal responding to the inquiry in accordance with the inquiry, an output unit that outputs questions for ascertaining details of the inquiry to the user terminal before connection made by the transmission unit, and a determination unit that determines a mode of the questions made by the output unit in accordance with an operating status of the operator terminal that can respond to the inquiry.