A display device displaying_two modes of two-dimensional images and three-dimensional images as mutually excluded alternatives depending on the alignment state of a liquid crystal region, and comprising: a display element configured to emit an image signal comprising a right-eye image signal and a left-eye image signal and including, spatially separated from each other, an UR region for generating the image signal for the right eye and an UL region for generating the image signal for the left eye; and a liquid crystal lens panel that comprises a lens layer comprising the liquid crystal region formed by liquid crystal molecules, and that is positioned such that the image signal emitted from the display element can be incident thereon, wherein the liquid crystal region is configured to be convertible between a cholesteric alignment state and a non-cholesteric alignment state, wherein the liquid crystal molecules in the cholesteric alignment state form plural layers and a director of an individual layer is aligned while being twisted along a helical axis, wherein the helical axis of the cholesteric alignment state is aligned parallel to a surface of the lens layer, wherein the liquid crystal region in a non-voltage applied state is in the cholesteric alignment state and the cholesteric alignment state switches to the non-cholesteric alignment state when a voltage is applied to the liquid crystal region, wherein in a state where the liquid crystal region is in the cholesteric alignment state, light linearly polarized in a direction perpendicular to the helical axis of the cholesteric alignment state and passing through the liquid crystal region is emitted according to position of incident light to display the three-dimensional images, such that the image signals for the right eye and left eye generated from the UR and UL regions of the display element are separated from each other to be then output in different directions, wherein in a state where the liquid crystal region is in the non-cholesteric alignment state, light linearly polarized in the direction perpendicular to the helical axis of the cholesteric alignment state and passing through the liquid crystal region is emitted as it is regardless of position of the incident light to display the two-dimensional images, wherein the UR region and UL region are alternately arranged in a plane, wherein at least one arrangement direction of those alternating regions is within said plane; wherein said arrangement direction and the helical axis direction are parallel to each other; and wherein the liquid crystal lens panel is arranged such that the image signals generated in a pair of the UR and UL regions are incident on a 1/2 pitch of the liquid crystal region in the cholesteric alignment state. a display element configured to emit an image signal comprising a right-eye image signal and a left-eye image signal and including, spatially separated from each other, an UR region for generating the image signal for the right eye and an UL region for generating the image signal for the left eye; and a liquid crystal lens panel that comprises a lens layer comprising the liquid crystal region formed by liquid crystal molecules, and that is positioned such that the image signal emitted from the display element can be incident thereon, wherein the liquid crystal region is configured to be convertible between a cholesteric alignment state and a non-cholesteric alignment state, wherein the liquid crystal molecules in the cholesteric alignment state form plural layers and a director of an individual layer is aligned while being twisted along a helical axis, wherein the helical axis of the cholesteric alignment state is aligned parallel to a surface of the lens layer, wherein the liquid crystal region in a non-voltage applied state is in the cholesteric alignment state and the cholesteric alignment state switches to the non-cholesteric alignment state when a voltage is applied to the liquid crystal region, wherein in a state where the liquid crystal region is in the cholesteric alignment state, light linearly polarized in a direction perpendicular to the helical axis of the cholesteric alignment state and passing through the liquid crystal region is emitted according to position of incident light to display the three-dimensional images, such that the image signals for the right eye and left eye generated from the UR and UL regions of the display element are separated from each other to be then output in different directions, wherein in a state where the liquid crystal region is in the non-cholesteric alignment state, light linearly polarized in the direction perpendicular to the helical axis of the cholesteric alignment state and passing through the liquid crystal region is emitted as it is regardless of position of the incident light to display the two-dimensional images, wherein the UR region and UL region are alternately arranged in a plane, wherein at least one arrangement direction of those alternating regions is within said plane; wherein said arrangement direction and the helical axis direction are parallel to each other; and wherein the liquid crystal lens panel is arranged such that the image signals generated in a pair of the UR and UL regions are incident on a 1/2 pitch of the liquid crystal region in the cholesteric alignment state.