A medical X-ray apparatus comprising a supporting part for supporting an X-ray generator and a two-dimensional X-ray detector while interposing an object to be examined therebetween, a radiation area restricting part for restricting a radiation area of X-ray generated from the X-ray generator, and a scan driving part for scanning the object with the X-ray restricted by the radiation area restricting part as X-ray beam and for executing radiography. A direction intersecting with X-ray scan direction is defined as a height direction, the apparatus further comprises a radiation area setting part for setting at least one of both ends of width of the X-ray beam in the height direction at a desired position in accordance with the position of an interested area of the object; and the X-ray beam is irradiated only to the radiation area as set by the radiation area setting part with its beam width in height direction restricted by the radiation area restricting part.