The present disclosure aims to make it possible to simultaneously establish communication between many freely-selected radio terminals without using a complex relay network or a plurality of radio relays. The present disclosure is a communication network system including: a plurality of optical-radio converters 521-1 to 521-n that convert a radio signal and an optical fiber radio signal into each other; and a path controller that is connected to the plurality of optical-radio converters 521-1 to 521-n through optical fiber transmission lines 531-1 to 531-n, receives input of an optical fiber radio signal transmitted from any optical-radio converter of the plurality of optical-radio converters 521-1 to 521-n from the optical fiber transmission line connected to the optical-radio converter, and outputs the optical fiber radio signal to the optical fiber transmission line connected to a set optical-radio converter of the plurality of optical-radio converters 521-1 to 521-n.