The invention relates to an X-ray apparatus which includes an X-ray source (2) for the emission of a conical X-ray beam and an X-ray detector (3) for the multiple detection of the X-rays after their passage through an object to be examined, being arranged along an object axis (4), while the X-ray source (2) and the X-ray detector (3) are displaced along a trajectory. In order to increase the size of the reconstructable examination zone without increasing the size of the X-ray detector, and in order to minimize the problem caused by projections truncated in the transverse direction, the invention proposes an X-ray apparatus which includes means (12, 14, 15) for changing the position and/or the orientation of the X-ray detector (3) relative to the X-ray source (2) and a control unit (11) for displacing the X-ray source (2) and the X-ray detector (3) along the trajectory and for controlling the position and/or the orientation of the X-ray detector (3) during the detection of the X-rays.