Providing a radiation emission unit that includes a radiation source and outputs a fan beam of radiation, a diffraction grating onto which radiation outputted from the radiation emission unit is emitted, and a periodic information imaging radiation image detector that includes multiple linear electrodes and detects periodic information of radiation diffracted by the diffraction grating, disposing the radiation emission unit and the periodic information imaging radiation image detector such that an extending direction of the linear electrodes of the periodic information imaging radiation image detector is perpendicular to a fan surface of the fan beam having a larger spread angle, and configuring the radiation emission unit to scan the fan beam in the perpendicular direction.