Abstract: A hardware system for inputting a 3D image in a flat panel includes: a 3D image source input unit which is mounted on a 3D monitor equipped with a lenticular lens for transferring a left eye image and a right eye image on a front surface of an LCD panel, respectively, to viewer's left eye and right eye and receives a 3D image in a side by side form in which a left eye image and a right eye image are combined in parallel left and right from a 3D image reproducing device, which is externally connected to the 3D monitor, through an image input terminal; and a viewer position tracker which is mounted on the 3D monitor to track, in real time, a viewer's position from an image photographed by a camera photographing a front of the 3D monitor.