There is provided a panoramic imaging apparatus which serves as a radiation imaging apparatus. The panoramic imaging apparatus includes an X-ray tube (31) radiating an X-ray as a radiation, a detector (32) outputting digital-quantity frame data corresponding to an incident X-ray, and moving means (23, 24) moving the pair of X-ray tube and the detector relatively to an object. The apparatus further includes means (12, 41, 52-57) for acquiring the frame data from the detector during movement of the X-ray tube and the detector, and means (12, 56) for optimally focusing a portion being imaged of the object using the acquired data and producing a three-dimensional optimally focused image in which the real size and shape of the portion being imaged are reflected.
