A radiation image reading device includes: a light scanning unit which scans excitation light to a surface of a recording medium having a radiation image recorded thereon along a scan line； a light detection unit which detects signal light emitted from the surface of the recording medium by the scanning of the excitation light within a detection surface intersecting the surface of the recording medium and including the scan line； and an optical filter which is disposed between the light detection unit and the surface of the recording medium. Each of a transmittance when the excitation light reflected from the surface of the recording medium is transmitted through the optical filter and a transmittance when the signal light emitted from the surface of the recording medium at an angle larger than a predetermined angle with respect to a direction perpendicular to the scan line within the detection surface is transmitted through the optical filter is smaller than a transmittance when the signal light emitted from the surface of the recording medium at an angle smaller than the predetermined angle with respect to a direction perpendicular to the scan line within the detection surface is transmitted through the optical filter.
