A display device having an automatically aligned display unit for displaying information, the display device comprising: a display main body having the display unit for displaying information; a rotary unit coupled to the display main body to rotate with the display main body and having a center of gravity that is eccentric from a center of the display main body; and a rotary base combined with the display main body or the rotary unit to rotate relative to the display main body or the rotary unit, wherein the rotary unit and the display main body combined with the rotary unit are rotated relative to the rotary base and keep aligned in the direction of gravity by gravity acting on the rotary unit and the rotary base keeps fixed when the display main body and the rotary unit rotate, wherein the display main body, the rotary unit, or the rotary base has a rotary shaft, the rotary shaft allows the display main body and the rotary unit combined with the display main body to rotate relative to the rotary base, and the rotary unit and the display main body combined with the rotary unit are rotated about the rotary shaft, wherein the rotary shaft has a body, and a head formed at an end of the body and having a lateral cross-section larger than that of the body, and the body and the head are covered with a cover detachably coupled to the rotary base, wherein a bearing fitted around the rotary shaft is disposed between the display main body and the rotary base, and wherein the bearing is disposed in a space defined by a depression formed toward the display main body on the rotary base, a cover detachably coupled to the rotary base, and the rotary shaft. a display main body having the display unit for displaying information; a rotary unit coupled to the display main body to rotate with the display main body and having a center of gravity that is eccentric from a center of the display main body; and a rotary base combined with the display main body or the rotary unit to rotate relative to the display main body or the rotary unit, wherein the rotary unit and the display main body combined with the rotary unit are rotated relative to the rotary base and keep aligned in the direction of gravity by gravity acting on the rotary unit and the rotary base keeps fixed when the display main body and the rotary unit rotate, wherein the display main body, the rotary unit, or the rotary base has a rotary shaft, the rotary shaft allows the display main body and the rotary unit combined with the display main body to rotate relative to the rotary base, and the rotary unit and the display main body combined with the rotary unit are rotated about the rotary shaft, wherein the rotary shaft has a body, and a head formed at an end of the body and having a lateral cross-section larger than that of the body, and the body and the head are covered with a cover detachably coupled to the rotary base, wherein a bearing fitted around the rotary shaft is disposed between the display main body and the rotary base, and wherein the bearing is disposed in a space defined by a depression formed toward the display main body on the rotary base, a cover detachably coupled to the rotary base, and the rotary shaft.