A communication apparatus executes authentication via wireless communication with a mobile device and, based on an authentication process, controls execution of a vehicle operation requested by a user. The communication apparatus includes a detection unit configured to detect closure of a door of a vehicle, an authentication processing unit configured to determine, in response to detection of the closure of the door by the detection unit, whether a specific mobile device is inside the vehicle by executing a first authentication process corresponding to a vehicle operation for which a highest security is set, among a plurality of vehicle operations that can be requested by the user, and an execution unit configured to execute, when the authentication processing unit has determined that the specific mobile device is inside the vehicle, a requested vehicle operation requestable from an inside of the vehicle and included in the plurality of vehicle operations.