This radiation image reading device is provided with: a light scanning unit that scans, with excitation light and along a scan line, a surface of a recording medium having a radiation image recorded therein； a light detection unit that detects, in a detection plane including the scan line and intersecting with the surface of the recording medium, signal light which is released from the surface of the recording medium as a result of scanning with the excitation light； and an optical filter that is disposed between the surface of the recording medium and the light detection unit. The transmission rate at which the excitation light, reflected by the surface of the recording medium, passes through the optical filter, and the transmission rate at which the signal light, released from the surface of the recording medium so as to form an angle larger than a predetermined angle relative to a direction perpendicular to the scan line within the detection plane, passes through the optical filter, are each smaller than the transmission rate at which the signal light, released from the surface of the recording medium so as to form an angle smaller than the predetermined angle in the direction perpendicular to the scan line within the detection plane, passes through the optical filter.L'invention concerne un dispositif de lecture d'image de rayonnement comportant : une unité de balayage de lumière qui balaie, avec une lumière d'excitation et le long d'une ligne de balayage, une surface d'un support d'enregistrement sur lequel est enregistrée une image de rayonnement ； une unité de détection de lumière qui détecte, dans un plan de détection comprenant la ligne de balayage et se croisant avec la surface du support d'enregistrement, une lumière de signal qui est libérée à partir de la surface du support d'enregistrement suite au balayage avec la lumière d'excitation ； et un filtre optique qui est disposé entre la surface du support d'enregistrement et l'unité de détection de lumière
