To implement highly-reliable information transmission to a plurality of counterparties by using one radio resource. A transmission information construction unit 104 of a base station 500 divides image information, designate order number thereto, and performs transmission multiple times at slots notified with notification information. A control unit 620 of a sub station 600 receives the notification information, establishes synchronization of TDMA and frequency hopping with the base station 500, performs reception of image information at a slot notified with the notification information, discards redundantly-received image information based on the order numbers, and performs displaying the image information.