A compensation circuit 76 of an AEC unit 67 of an electronic cassette 13 defines the detection signal of a detection pixel 65 of the electronic cassette 13 as a detection signal corresponding to the detection signal of an old AEC sensor 25. The compensation circuit 76 performs compensation so as to exclude the influence on the detection signal due to a difference in the configuration of an intermediate member disposed between an X-ray source 10 and an FPD 35 of the electronic cassette 13 when the detection pixel 65 is used as an AEC sensor instead of the old AEC sensor 25. The detection signal is transmitted from a detection signal I/F 80 to a detection signal I/F 26 of a source control device 11 as it is (instantaneous value) or as an accumulated value obtained using an integration circuit 77.
