PURPOSE: To provide a network congestion control method which minimizes deterioration of the service grade and at the same time recovers the congestion state as soon as possible in a multiple destination simultaneous multi-address communication system.

CONSTITUTION: The same video information is simltaneously distributed to the terminals 14 and 15 via a network 13 by a network congestion control method in a multiple destination simultaneous multi-address communication system. An image distribution center 11 contains a means which detects the congestion state of the network 13. When the congestion state of the network 13 is detected, the quality of the images to be distributed are deteriorated and then restored when the congestion state is recovered (the 1st method). Meanwhile the non-preferential terminals are cut when the congestion state of the network 13 is detected (the 2nd method). Furthermore the 1st and 2nd methods are combined together in accordance with the degree of congestion. That is, if the congestion state is not recovered dispite deterioration of the image quality, the non-preferential terminals are successively cut.