Provided is a wearable device including a main body that is configured to be worn on a specific portion of a user's body, a sensing unit, provided in the main body, that senses a biological signal of a user, a storage unit that collects log information relating to the biological signal, and in which an index pattern relating to a state of the user included in the collected log information is stored, and a controller that sets a reference driving index, using the stored index pattern, in which when it is sensed that the user gets in a vehicle, the controller determines a current driving index corresponding to the biological signal that is sensed before and after the user gets in the vehicle, based on the reference driving index being set, and outputs feedback that notifies the state of the user that corresponds to a result of the determination.