According to one embodiment, a display device includes a switching liquid crystal unit, a display, and a controller. The switching liquid crystal unit includes optical elements switching an aperture pattern including an aperture portion and a light-shielding portion. The display overlaps the switching liquid crystal unit and displays parallax images including right and left eye images. The controller acquires positional information relating to a position of a viewer, and controls a position of the aperture pattern. The controller switches the aperture pattern from a first aperture pattern to a second aperture pattern so that a right eye always views the right eye image and a left eye always views the left eye image, and starts the switching before the viewer moves to an optimal switching position where a luminance viewed from the first aperture pattern is substantially equal to a luminance viewed from the second aperture patterns.