The image pickup apparatus of the radiological imaging apparatus of the present invention includes many detector units, a ring-shaped detector support member and an X-ray source circumferential transport apparatus. Each of the detector units is attached to the detector support section in a detachable manner. A plurality of radiation detectors provided for the detector units are arranged in three layers in the radius direction of the detector support member and in three columns in the axial direction of the detector support member. Since the radiation detectors are arranged in three layers in the radius direction, it is possible to recognize the detection position of radiation in the radius direction in detail. Furthermore, since the detector units are attached in a detachable manner, it is easy to replace damaged radiation detectors.