The X-ray flat panel detector 3 is provided in the radiation imaging apparatus of the present invention, by providing the first switching unit 13 to connect or disconnect the data lines to each other for reading the charge signals, to select an imaging mode and a normal pixel addition mode it is possible to perform X-ray imaging with. Also, by providing the second switching portion 14 between the voltage signal detection unit 23 and the data line further, each time selecting a gate line, a signal amplifying circuit 26 and a charge detection amplifier circuit 24 of the voltage signal detector 23 it is possible to alternately perform initialization. As a result, it is possible that while it is possible to fully initialize the signal amplifier circuit 26 and a charge detection amplifier circuit 24, is read out at high speed X-ray detection signal.本発明の放射線撮像装置に備わるX線平面検出器3には、電荷信号を読み出すデータ線同士を接続または遮断する第1切り替え部13を備えることで、画素加算モードと通常の撮像モードとを選択してX線撮像を行うことができる。また、さらにデータ線と電圧信号検出部23との間に第2切り替え部14を備えることで、ゲート線を選択する度に、電圧信号検出部23内の電荷検出増幅回路24および信号増幅回路26の初期化を交互に行うことができる。この結果、電荷検出増幅回路24および信号増幅回路26を十分に初期化することができつつ、X線検出信号を高速に読み出すことができる。
