An advertisement display system includes a photograph unit for taking a photograph of a signal light of a signal such as a traffic signal or an alarm for a railway crossing, a computer for analyzing the signal condition such as lighting or blinking of the signal light from image data thus photographed by the photograph unit, and a display unit for displaying advertisement display information which is stored in advance in the computer or the display unit in conjunction with the lighting or blinking condition of the signal light analyzed by the computer and displays a display body having a content correlated with the signal condition of the signal on the display unit.