PROBLEM TO BE SOLVED: To provide a technique advantageous for high accuracy of an AEC of a radiation imaging device.SOLUTION: A radiation imaging device comprises: a plurality of pixels arranged in a column (so as to form a plurality of columns and a plurality of rows)； a plurality of row signal lines； and a processor. The plurality of pixels is arranged between a first row and a second row of the plurality of rows so that the number of a first pixel and a second pixel which occurs a signal that different each other by receiving a radiation of the same radiation dose is different each other. The processor acquires the signal of a row signal line of the first row as a first signal while maintaining the plurality of pixels in a non-activation state after irradiation of the radiation is started, acquires the signal of the row signal line of the second row as a second signal, calculates an irradiation amount of the radiation on the basis of the difference of the fist signal and the second signal, and executes an AEC on the basis of a result of the calculation.SELECTED DRAWING: Figure 2【課題】放射線撮像装置のＡＥＣの高精度化に有利な技術を提供する。【解決手段】放射線撮像装置は、行列状に（複数の行および複数の列を形成するように）配列された複数の画素と、複数の列信号線と、プロセッサとを備え、前記複数の画素は、前記複数の列のうちの第１列および第２列の間で、互いに同じ線量の放射線を受けて互いに異なる信号を発生する第１画素および第２画素のそれぞれの数が互いに異なるように配列されており、前記プロセッサは、放射線の照射の開始後、前記複数の画素のそれぞれを非活性状態に維持したまま前記第１列の列信号線の信号を第１信号として取得し且つ前記第２列の列信号線の信号を第２信号として取得し、前記第１信号と前記第２信号との相違に基づいて前記放射線の照射量を算出し、該算出の結果に基づいてＡＥＣを行う。【選択図】図２
