To provide the display system which never has a hidden window.

A storage device 103 is equipped with a display condition storage part 131 and a communication device operation history storage part 132 and a data processor 102 is equipped with a history managing means 121 which registers an operation history in the communication device operation history storage part, a display condition managing means 122 which refers to currently registered condition information in the display condition storage part 131, a display history determining means 123 which determines whether or not display conditions are actually displayed, a history display means 124 which displays a decided history to be displayed in a window 104, and a condition area display means 125 which divides the window 104 and displays a condition area, so that only a communication operation device which meets the display conditions is displayed. When a new history is generated and when display conditions are added, the display conditions and history are managed by the storage device 103 so that no mutual inconsistency is generated.