A proxy response apparatus is equipped with a module that obtains and retains request messages and response messages exchanged between a client and main and backup servers, a module for detecting a failure in the main server, a module for sending to the backup server requests retained when a failure occurs in the main server, a module for receiving responses from the backup server, a module for detecting communications status between the client and the main server at the time the failure occurred, and a module for responding in place of the main server in order to resume communicating state from the previous state.