PROBLEM TO BE SOLVED: To provide a radiation imaging apparatus and a heat diffusion method capable of improving temperature unevenness of a radiation detector. SOLUTION: A radiation detector in which a plurality of pixels accumulating charges according to the irradiated radiation are arranged in a two-dimensional manner, a control unit for controlling the radiation detector, and an airflow are guided in a predetermined guidance direction. A guide unit is provided, and has a heat sink that dissipates heat from the control unit, and a radiation detection surface that houses the radiation detector, the control unit, and the heat sink and is irradiated with the radiation emitted from the radiation irradiation unit that emits radiation. A low heat conductive member provided between the storage unit and the radiation detector and the control unit, whose thermal conductivity is lower than a predetermined thermal conductivity, and a low thermal conductive member provided in the vicinity of the low thermal conductive member, the heat of the low thermal conductive member A radiation imaging device equipped with a heat diffusion member that diffuses radiation. [Selection diagram] Fig. 1【課題】放射線検出器の温度ムラを改善することができる放射線画像撮影装置及び熱拡散方法を提供する。【解決手段】照射された放射線に応じた電荷を蓄積する複数の画素が二次元状に配置された放射線検出器と、放射線検出器を制御する制御部と、所定の誘導方向に気流を誘導する誘導部が設けられ、制御部の熱を放熱するヒートシンクと、放射線検出器、制御部、及びヒートシンクを収納し、放射線を射出する放射線照射部から射出された放射線が照射される放射線検出面を有する収納部と、放射線検出器と制御部との間に設けられ、熱伝導率が予め定められた熱伝導率よりも低い低熱伝導部材と、低熱伝導部材の近傍に設けられ、低熱伝導部材の熱を拡散する熱拡散部材と、を備えた放射線画像撮影装置。【選択図】図１
