A radiation imaging system (11) has a radiation generation device (12), an FPD cassette (13), and a console (14). The console (14) judges whether or not the FPD cassette (13) is in a good communication state repeatedly once every thirty seconds. Upon receiving a radiography order, the console (14) changes repetition intervals from thirty seconds to three seconds, and keeps judging the communication state of the FPD cassette (13). The repeated judgment is continued until a shutter button is pressed. Upon the press of the shutter button, the radiation generation device (12) emits radiation to carry out radiography.
