An electronic device for diagnosing a fault of a plurality of external devices is disclosed. The electronic device comprises a communication unit and a processor. The processor receives, from the plurality of external devices, information related to an operation of the plurality of external devices through the communication unit; on the basis of the information related to the operation of any one of the plurality of external devices, determines whether any external device is operating abnormally; when the external device is operating abnormally, diagnoses the cause of the abnormality on the basis of the information related to the operation of the one external device and information related to an operation of another external device of the plurality of external devices that is relevant to the operation of the one external device; and provides, via the communication unit, information on the diagnosed abnormality to the at least one of the one external device and a communication device of a user of the external devices.