The present invention is directed to perform high-reliable authentication using a one-way function that a communication is a communication which was performed with the same apparatus to be authenticated by storing a password only in an apparatus to be authenticated (it is unnecessary to store a password in both of an authentication apparatus and an apparatus to be authenticated) without transmitting a challenge code. When a setting is updated in a setting management server, authentication is performed by using a one-time password obtained last time. A sound communication terminal performs a process using a hash function once on a one-time password transmitted this time, and performs authentication by determining whether the processed one-time password matches a one-time password obtained last time or not. Whether the information at the time of the change in the setting is proper or not is determined by a sound terminal.