PURPOSE: To attain high speed congestion-control in a node by respectively providing a buffer accumulation quantity supervisory means and a congestion notice adding means for an input/output port on a congestion supervisory-side and a congestion notice detection means and a packet regulation means for an input/output port on a packet regulation-side.

CONSTITUTION: When the quantity of packets accumulated in the transmission buffer 18 of the input/output port 15 is more than a prescribed quantity, the buffer accumulation supervisory means 19 detects it and the congestion notice adding means 17 adds a congestion notice to the packet of a reception buffer 16. The packet outputted from the reception buffer 16 is inputted to the transmission buffer 13 of the input/output port 10 through a switch 20. When the congestion notice detecting means 14 detects the congestion notice added to the packet of the transmission buffer 13, the packet restriction means 12 executes restriction by stopping the output of the packet to the switch 20 from a reception buffer 11 or reducing the speed to be outputted.