A portable radiographic imaging system includes an FPD cassette and a portable console, each of which is configured to wirelessly communicate with a portable relay unit. The relay unit prohibits a radiation generator from emitting radiation when judging that a wireless communication connection has not been established between the relay unit and the radiation generator, and allows the radiation generator to emit radiation when judging that the wireless communication connection has not been established between the relay unit and the radiation generator after an interlock release signal is transferred from the console or the like to the radiation generator.
