PURPOSE: To avoid an error in restriction instruction and to reduce the time required for the processing with immediacy by identifying congestion identification information included in maintenance operation information from an electronic exchange and sending traffic restriction instruction information automatically to the electronic exchange when the congestion is discriminated.

CONSTITUTION: A maintenance operation system 2 fetches maintenance operation information through an input output controller(IOC) 27 and sends it to a congestion restriction device 20. An identification section(IDT) 21 of the congestion restriction device 20 identifies congestion, a discrimination section(DCS) 22 discriminates the congestion to read a traffic restriction instruction registered in a storage section(MEM) 26 via a traffic restriction command registration control section(RGC) 25 from an input terminal equipment(ITE) 29 in advance. Thus, a traffic restriction section(TRG) 24 sends the traffic restriction instruction information to the IOC 27. Thus, the traffic restriction instruction is implemented in a short time with immediacy.