According to various embodiments, an electronic device comprising a memory; a communication module; and a processor, operatively connected to the memory and the communication module, and configured to, if a locked state of the electronic device and a first state of the electronic device are identified, when a first user utterance is acquired that requests a task executable in an unlocked state of the electronic device, change an unlocking type of the electronic device to an unlocking type of an external device, based on first information of the external device, the external device being communicatively connected to the electronic device through the communication module, unlock the electronic device, which is configured with the unlocking type of the external device, based on user authentication information acquired from the external device, and execute the task corresponding to the first user utterance. Various other embodiments may be provided. Meanwhile, a method of performing an authentication operation by the electronic device may be performed using an artificial intelligence model.