A head-mounted display device for providing augmented reality contents to a wearer includes an eye tracker, a light projector, a beam steerer and a combiner. The eye tracker is configured to determine a position of a pupil of an eye of the wearer. The light projector is configured to project light for rendering images. The beam steerer is configured to change a direction of the light from the light projector based on the position of the pupil. The combiner is configured to combine the light from the light projector and light from an outside of the head-mounted display device for providing an overlap of the rendered image and a real image that corresponds to the light from the outside of the head-mounted display device.