A picture display device for displaying a video signal supplied from a data process device, comprising: display means operable to display a video signal; display control means operable to control said display means to display a plurality of video signals (4A...4N) supplied from a plurality of data process devices (2A...2N) at a time; input device connection means to which an input device (3, 14) for outputting a first control signal is output corresponding to a user's operation; control signal output means operable to output the first control signal (5A, 5B) supplied from said input device (3, 14) to the plurality of data process devices (2A...2N), wherein said display control means is composed of: memory means operable to store the plurality of video signals supplied from the plurality of data process devices; and control means operable to read a video signal for one screen of said display means from said memory means characterized in that, said display control means is operable to control said memory means to store the plurality of video signals in such a manner that the addresses thereof become successive and said read control means is operable to control said memory means to designate a range of successive addresses corresponding to a video signal for one screen of said display means and read the video signal from said memory means so as to cause said display means to display the plurality of video signals at a time. display means operable to display a video signal; display control means operable to control said display means to display a plurality of video signals (4A...4N) supplied from a plurality of data process devices (2A...2N) at a time; input device connection means to which an input device (3, 14) for outputting a first control signal is output corresponding to a user's operation; control signal output means operable to output the first control signal (5A, 5B) supplied from said input device (3, 14) to the plurality of data process devices (2A...2N), wherein said display control means is composed of: memory means operable to store the plurality of video signals supplied from the plurality of data process devices; and control means operable to read a video signal for one screen of said display means from said memory means characterized in that, said display control means is operable to control said memory means to store the plurality of video signals in such a manner that the addresses thereof become successive and said read control means is operable to control said memory means to designate a range of successive addresses corresponding to a video signal for one screen of said display means and read the video signal from said memory means so as to cause said display means to display the plurality of video signals at a time. memory means operable to store the plurality of video signals supplied from the plurality of data process devices; and control means operable to read a video signal for one screen of said display means from said memory means characterized in that, said display control means is operable to control said memory means to store the plurality of video signals in such a manner that the addresses thereof become successive and said read control means is operable to control said memory means to designate a range of successive addresses corresponding to a video signal for one screen of said display means and read the video signal from said memory means so as to cause said display means to display the plurality of video signals at a time.