Provided is a navigation technique which allows a person other than a user who receives a route guide to operate a navigation device through an interaction process. The navigation device is characterized by being provided with an instruction reception means, a process means, and an output means. The instruction reception means receives an instruction for a process from an external device. The process means executes a process in accordance with the instruction received by the instruction reception means. The output means outputs output information which is obtained as the result of the process executed by the process means.