The present invention enables the occurrence of noise to be detected, and an imaging operation controlled, without any delay in cases in which noise caused by external disturbance occurs. Namely, upon irradiation with radiation, electrical signals (charge data) output from radiation detection pixels during a charge accumulation period of charges generated according to the radiation are detected in a signal detection circuit during a specific detection period, and a controller determines whether or not change with time of the electrical signals (charge data) exhibits predetermined characteristics of noise. If such characteristics are present, noise is determined to have occurred, operation of an electronic cassette is stopped, the charge accumulation period is interrupted (ceased), and transition is made to a radiation detection period.
