An autostereoscopic display having an improved 2D / 3D mode switchable structure. The autostereoscopic display includes: a
display device to display an image, and a
parallax barrier unit to transmit all incident light in a 2D mode, and to separate a left-eye image and a right-eye image by forming a barrier in a 3D mode. The
parallax barrier unit includes: a
polarizer disposed in an
optical path of the image displayed by the
display device to transmit light having a predetermined
polarizer polarization direction, a first plane array including first birefringent elements, which change a polarization direction of light transmitted through the
polarizer into a first direction, and second birefringent elements, which change a the polarization direction of the light transmitted through the polarizer into a second direction opposite to the first direction, the first and second birefringent elements alternating with each other, a second plane array facing the first plane array, and including third birefringent elements, which change a polarization direction of light transmitted through the first plane array into a third direction, and fourth birefringent elements, which change the polarization direction of the light transmitted through the first plane array into a fourth direction that is opposite from the third direction, the third and fourth birefringent elements alternating with each other, and an analyzer facing the second plane array to transmit only light having a predetermined analyzer polarization direction from among light transmitted through the second plane array, wherein at least one of the first and second plane arrays is movable to control relative positions of the first and second birefringent elements and the third and fourth birefringent elements to selectively display a 2D image or a 3D image.