A channel switching controller 18 is applied to a communication network such as an ISDN. The network has a first information processor 10, an exchange 15 and a second information processor 17. If communication between the first and second information processors fails, the first information processor 10 notifies the exchange 15 that a communication channel, terminal, or line (telephone number) presently being used will be switched to another. In response to the notification, the exchange 15 holds the current call. The first information processor 10 resumes communication through the newly selected communication channel, terminal, or line (telephone number), and the exchange releases the call, to continue the communication between the first and second information processors. The first information processor may notify the second information processor of the failure of the communication channel, terminal, or line (telephone number), to let the second information processor make a call accordingly.