A display control device for controlling displaying of images taken by a plurality of cameras each having a function of changing a zoom magnification includes: an operation unit including an operation element provided for each of the cameras to accept an operator's operation of setting the zoom magnification of the cameras, the operation unit being configured to output a input pulse signal corresponding to an operation amount of the operation element; and a W/T pulse convertor configured to convert the input pulse signal to a reference pulse signal that is uniformized variations in the zoom magnification of respective cameras with respect to a predetermined operation amount of the operation element, and output the second control signal to a corresponding camera.