To arbitrarily divide a video signal transmitted from plural communication terminals and to composite them into or single screen and to display the composited picture in a display screen of each communication terminal at the same time.

This is a communication system is of a constitution, in which a center device 1 and repeater devices 2 provided with plural access points respectively are bidirectionally connected to each other by way of a communication line 3, a communication terminal 4 for members is connected to any of the repeater devices 2 and a communication terminal 5 for a lecturer is connected to the center device 1. In this case, the center device 1 arbitrarily divides video signals transmitted from each of the connected communication terminals 4 and 5 within a single picture, composites them and transmits these composited video signals to each of the communication terminals 4 and 5. Moreover, each of the communication terminals 4 and 5 divides the video signals of all the connected communication terminals 4 and 5 on a single screen and displays them simultaneously by displaying the transmitted composited signals on the screen.