Radiation detector and method for manufacturing radiation detector

Provided are: a radiation detector which has achieved excellent physical strength by devising the method for manufacturing the radiation detector and is capable of stably obtaining a radiation transmission image that has excellent visibility; and a method for manufacturing a radiation detector. An X-ray detector (10) of the present invention is provided with an active matrix substrate (4) that is subjected to a nitrogen component oxidation treatment. A first high-resistance film (7) is then formed on the upper surface of the active matrix substrate (4) wherein the nitrogen component is in an oxidized state. By carrying out a novel treatment on the active matrix substrate (4) as explained above, the active matrix substrate (4) has achieved high affinity to the first high-resistance film (7). Consequently, the first high-resistance film (7) is firmly bonded to the active matrix substrate (4), thereby improving the physical strength of the X-ray detector (10).