To easily and surely switch a band control system.

A band control router 16 which is provided with an interface 21 capable of controlling start/stop performs band control to a packet transmitted through a network connection line 19, and transmits the packet from a packet line 20. A line router 14 performs band control to the packet transmitted through the packet line 20 according to registered definition information, transmits it from a parallel line 11, and transmits the packet transmitted through the network connection line 19 from the parallel line 11 by performing load distribution. An operation management device 15 stops the interface 21 in an initialized state, and allows the line router 14 to execute the load distribution band control. Then, the definition information for the band control is registered in each line router 14 and band control router 16, and then the interface 21 is started so that the band control can be executed by the band control router 16 and the line router 14.