In a radiation detection device in which light that is generated at a phosphor layer based on absorbed radiation, the phosphor layer being constituted by connecting side faces of columnar phosphors to each other, is converted into an electric charge at a photoelectric conversion element portion and radiation is detected based on the electric charge, the phosphors have larger column diameters in peripheral regions of the phosphor layer than in a central region thereof. Further, the phosphor layer has a film thickness that is smaller in its peripheral regions than in a central region thereof, thereby preventing breakage of the phosphors.