The invention intends to achieve new additions of terminals that use a wireless LAN with a simple process, while preventing leakage of data indicating cipher keys. The access point is notified of the cipher systems adaptable to the terminals. The access point narrows the cipher systems adaptable to itself, sets the cipher keys and notifies them, and also determines the station IDs for the cipher keys each. Thereafter, when the access point modifies the cipher systems based on the security policy, the access point adopts the station IDs corresponding to the cipher systems each. Therefore, the terminals specify the cipher systems based on the station IDs, and perform wireless communications by using the cipher keys notified in advance.