A wireless network system provided with a setting change instruction unit transmitting setting change instructions to all of the client systems based on a setting change request of the wireless network from a single client system and a wireless communication control system side setting content update unit updating the wireless network setting content in the wireless communication control system in synchronization with the processing of the setting change instruction unit. Each of the client systems is provided with a setting change instruction reception unit receiving a setting change instruction from the setting change instruction unit and a client system side setting content update unit updating the wireless network setting content in the client system based on the setting change instruction received by the setting change instruction reception unit.