PROBLEM TO BE SOLVED: To carry out the same AEC as before changing an AEC sensor without modifying an existing apparatus when the AEC sensor is changed.SOLUTION: 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 imaging area 36 of 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.COPYRIGHT: (C)2013,JPO&INPIT【課題】AECセンサを変更した場合に既存の装置を改造することなく変更前と同じAECを行う。【解決手段】電子カセッテ13のAEC部67の補正回路76は、電子カセッテ13の検出画素65の検出信号を旧AECセンサ25の検出信号に相当する検出信号とする。補正回路76は、旧AECセンサ25に代えて検出画素65をAECセンサとして用いた場合のX線源10と電子カセッテ13のFPD35の撮像面36との間に配置される中間部材の構成の違いによる検出信号への影響を排除するように補正を行う。検出信号は、そのまま(瞬時値)、または積分回路77で積算値とされて、検出信号I/F80から線源制御装置11の検出信号I/F26に向けて送信される。【選択図】図5