To make it possible to relatively simply implement accurate AEC.SOLUTION: A radiation imaging device comprises: an imaging unit at which a plurality of sensors capable of detecting radiation are arranged； and a processing unit that generates a signal for finishing radiation irradiation to the imaging unit, on the basis of a part of a plurality of control sensors, sensors of the plurality of sensors. The processing unit performs first operation of acquiring a ratio between signal values of the plurality of control sensors in a first period after a start of the radiation irradiation to the imaging unit and second operation that on the basis of a signal of a part of the plurality of control sensors and the ratio acquired by the first operation, calculates a signal of the other control sensor in a second period after the first period.SELECTED DRAWING: Figure 1【課題】ＡＥＣの高精度化を比較的簡便に実現可能にする。【解決手段】放射線を検出可能な複数のセンサが配列された撮像部と、前記撮像部への放射線照射を終了させるための信号を前記複数のセンサの一部である複数の制御用センサの信号に基づいて発生する処理部と、を備える放射線撮像装置であって、前記処理部は、前記撮像部への放射線照射が開始された後の第１期間において、前記複数の制御用センサ間の信号値の比を取得する第１動作と、前記第１期間後の第２期間において、前記複数の制御用センサのうちの一部の制御用センサの信号と、前記第１動作で得られた前記比とに基づいて、他の制御用センサの信号を算出する第２動作と、を行う。【選択図】図１
