The invention provides a wireless connection establishment method enabling determination of a transmission format while giving consideration to security when conducting a connection establishment needed to send and receive multimedia information between radio devices having a radio communication function. In the invention, a radio device control terminal requests an authentication server to conduct authentication with respect to radio devices requesting a connection and then an authentication process is performed by the authentication server. When the radio devices are authenticated properly, the radio device control terminal acquires each transmission format of the radio devices from an information management server to determine a radio transmission format common to these radio devices. The radio transmission format thus determined is sent to the radio devices, so that the radio devices establish a wireless connection with each other by use of the radio transmission format.