The invention prevents delays in the communication of stop signals which stop X ray irradiation. An electronic cassette (19) begins an accumulation operation and measurement of X ray dose in a FPD (23) when a synchronization signal representing the beginning of X ray irradiation is input from a radiation source control unit (15) which controls an X ray source (14). The electronic cassette (19) and a console (13) stop the respective communication units (42) from communicating anything other than a stop signal which stops X ray irradiation to the X ray source during the accumulation operation of the FPD (23). When the X ray dose reaches a previously established threshold the electronic cassette (19) sends a stop signal to the radiation source control unit via the console (13). Since all communication other than stop signals are stopped in the electronic cassette (19) and the console (13) delays of the stop signal due to congestion of communication or signal collision do not occur.
