A channel switching controller is applied to a communication network such as an ISDN. The network has a first information processor, an exchange, and a second information processor. The channel switching controller easily and speedily switches channels from one to another when a communication error occurs in the network. If communication between the first and second information processors fails, the first information processor notifies the exchange that a communication channel, terminal, or line (telephone number) that is presently being used will be switched to another. In response to the notification, the exchange holds the current call. The first information processor 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.