A radiation image acquisition device includes: a radiation source which emits radiation; a wavelength conversion member of a flat plate shape which generates scintillation light according to incidence of the radiation emitted from the radiation source and transmitted by an object; first imaging means which condenses and images the scintillation light emitted from an entrance surface for the radiation in the wavelength conversion member in a direction inclined with respect to a direction of a normal to the entrance surface; and second imaging means which condenses and images the scintillation light emitted from a surface opposite to the entrance surface in the wavelength conversion member in a direction inclined with respect to a direction of a normal to the opposite surface.