A radiation detection device for a foreign substance inspection using a subtraction method, which is configured to detect radiation in a first energy range and radiation in a second energy range higher than the radiation in the first energy range that are transmitted through a specimen and incident from a radiation incident direction, comprising: a first radiation detector that is positioned on the upstream side with respect to the radiation incident direction and is configured to detect radiation in the first energy range; and a second radiation detector that is positioned on the downstream side with respect to the radiation incident direction and is configured to detect radiation in the second energy range, wherein the first radiation detector includes a first scintillator layer that extends along an image detection direction and is configured to convert an image of radiation in the first energy range into an optical image, and a first pixel section that has a plurality of pixels arrayed along the image detection direction and is configured to acquire a first image based on the optical image converted by the first scintillator layer, the second radiation detector includes a second scintillator layer that extends along the image detection direction and is configured to convert an image of radiation in the second energy range into an optical image, and a second pixel section that has a plurality of pixels arrayed along the image detection direction and is configured to acquire a second image based on the optical image converted by the second scintillator layer, the thickness of the first scintillator layer is smaller than the thickness of the second scintillator layer, and the area of each pixel in the first pixel section is smaller than the area of each pixel in the second pixel section, wherein the area of each pixel in the first pixel section is the product of the pixel width in the image detection direction and the pixel width in the orthogonal direction orthogonal to the image detection direction, and the area of each pixel in the second pixel section is a product of the pixel width in the image detection direction and the pixel width in the orthogonal direction orthogonal to the image detection direction, and characterized in that the number of pixels in the first pixel section is greater than the number of pixels in the second pixel section, and the pixel pitch of the pixels in the second pixel section is n times the pixel pitch of the pixels in the first pixel section, where n is a positive integer. a first radiation detector that is positioned on the upstream side with respect to the radiation incident direction and is configured to detect radiation in the first energy range; and a second radiation detector that is positioned on the downstream side with respect to the radiation incident direction and is configured to detect radiation in the second energy range, wherein the first radiation detector includes a first scintillator layer that extends along an image detection direction and is configured to convert an image of radiation in the first energy range into an optical image, and a first pixel section that has a plurality of pixels arrayed along the image detection direction and is configured to acquire a first image based on the optical image converted by the first scintillator layer, the second radiation detector includes a second scintillator layer that extends along the image detection direction and is configured to convert an image of radiation in the second energy range into an optical image, and a second pixel section that has a plurality of pixels arrayed along the image detection direction and is configured to acquire a second image based on the optical image converted by the second scintillator layer, the thickness of the first scintillator layer is smaller than the thickness of the second scintillator layer, and the area of each pixel in the first pixel section is smaller than the area of each pixel in the second pixel section, wherein the area of each pixel in the first pixel section is the product of the pixel width in the image detection direction and the pixel width in the orthogonal direction orthogonal to the image detection direction, and the area of each pixel in the second pixel section is a product of the pixel width in the image detection direction and the pixel width in the orthogonal direction orthogonal to the image detection direction, and characterized in that the number of pixels in the first pixel section is greater than the number of pixels in the second pixel section, and the pixel pitch of the pixels in the second pixel section is n times the pixel pitch of the pixels in the first pixel section, where n is a positive integer.