An onboard device including: a display control section that, based on a detection result of a detection section for detecting targets at a periphery of a vehicle, displays an ego vehicle image depicting the vehicle together with a peripheral monitoring image on a display provided to the vehicle; a reception section that receives an operation of an occupant of the vehicle on the display; and an execution section that executes a predetermined processing related to a function of the vehicle at each section of the vehicle according to the operation received by the reception section.