PROBLEM TO BE SOLVED: To provide a radiation detector and a radiation image capturing apparatus capable of suppressing discontinuous bending of a sensor substrate using a flexible base material. A radiation detector is provided with a flexible substrate and a plurality of pixels formed on a first surface of the substrate and accumulating charges generated according to light converted from radiation. A sensor substrate including a layer, a conversion layer that is provided on the opposite side of the base material in the layer where the pixels are formed, and that converts radiation into light, a protective film that covers at least the conversion layer, and a flexible base material. A reinforcing member that reinforces and a supporting member that supports the sensor substrate together with the reinforcing member are provided. [Selection diagram] Fig. 3【課題】可撓性の基材を用いたセンサ基板が不連続に撓むことを抑制することができる放射線検出器及び放射線画像撮影装置を提供する。【解決手段】放射線検出器は、可撓性の基材、及び基材の第１の面に設けられ、かつ放射線から変換された光に応じて発生した電荷を蓄積する複数の画素が形成された層を含むセンサ基板と、画素が形成された層における基材と反対側に設けられ、放射線を光に変換する変換層と、少なくとも変換層を覆う保護膜と、可撓性の基材を補強する補強部材と、補強部材とともにセンサ基板を支持する支持部材と、を備える。【選択図】図３
