To provide a technology advantageous for suppressing power consumption of a radiation imaging apparatus in which exposure control is performed.SOLUTION: A radiation imaging apparatus includes: an imaging unit including a plurality of pixels for generating a radiation image； a detection unit for detecting a radiation ray for monitoring an incident dose of a radiation ray incident on the imaging unit； a processing unit for performing processing to read signals from the imaging unit and the detection unit so as to output signals based on the read signals； and a control unit for controlling the processing unit. The control unit causes the processing unit to be operated in a first power consumption mode before the start of radiation ray irradiation； causes the processing unit to perform a reset operation for resetting the plurality of pixels in the first power consumption mode； causes the processing unit to be operated in a second power consumption mode whose power consumption is larger than the first power consumption mode according to start information indicating the start of irradiation of the radiation ray to the imaging unit； and causes the processing unit to start outputting a signal for monitoring the incident dose based on the signals read from the detection unit in the second power consumption mode.SELECTED DRAWING: Figure 5【課題】露出制御を行う放射線撮像装置の消費電力の抑制に有利な技術を提供する。【解決手段】放射線画像を生成するための複数の画素を含む撮像部と、撮像部に入射する放射線の入射線量のモニタのために放射線を検出する検出部と、撮像部および検出部から信号を読み出し、読み出した信号に基づく信号を出力する処理を行う処理部と、処理部を制御する制御部と、を含む放射線撮像装置であって、制御部は、放射線の照射が開始される前に、処理部を第１の電力消費モードで動作させ、第１の電力消費モードにおいて、処理部に複数の画素をリセットするリセット動作を行わせ、撮像部への放射線の照射開始を示す開始情報に応じて、処理部を第１の電力消費モードよりも電力消費が多い第２の電力消費モードで動作させ、第２の電力消費モードにおいて、処理部に検出部から読み出した信号に基づく入射線量のモニタを行うための信号の出力を開始させる。【選択図】図５
