A service support device includes an information processing device. The information processing device is configured to deliver key information to a mobile terminal. The mobile terminal corresponds to each of a plurality of business operators that provide a user of a vehicle with a predetermined service using the vehicle. The key information is information for unlocking the vehicle, starting the vehicle, or unlocking and starting the vehicle when a predetermined transmission signal is transmitted toward the vehicle. The information processing device is configured to, when the mobile terminal corresponding to a first business operator among the plurality of business operators uses the key information, make coordination such that the mobile terminal corresponding to a second business operator among the plurality of business operators does not use the key information.