An exemplary embodiment of the present disclosure provides a method of recognizing, by a controller, an intention of a user who wears a head mounted display to which electroencephalogram electrodes are attached. The method includes obtaining brain signals for learning from each of the head mounted display and an additional electrode device coupled to the head mounted display, in a state where a training image causing brain signals is displayed on the head mounted display; learning a first relational model between electrodes of the head mounted display and electrodes of the additional electrode device using the brain signals for learning; measuring brain signals by the head mounted display decoupled with the additional electrode device, in a state where a specific image is displayed on the head mounted display; estimating brain signals of the additional electrode device non-measured, from the brain signals measured by the head mounted display based on the first relational model; and recognizing a user intention corresponding to the measured brain signals and the estimated brain signals.