A 2D and 3D image display apparatus including: a display panel forming an image by spatially modulating an input image signal; a polarization conversion device converting a polarization direction of a beam incident into the polarization conversion device according to a voltage applied in synchronization with the image signal; and a switching barrier unit including first polarization units having a first polarization direction and second polarization units having a second polarization direction in an alternate manner, and transmitting the beam passing the polarization conversion device through at least one of the first polarization unit and the second polarization unit. Therefore, a 3D image can be displayed without degrading a horizontal resolution thereof by using a combination of polarization devices with low fabrication costs, which may utilize a time-sequential display method.