According to one embodiment, an X-ray diagnostic apparatus includes an X-ray tube, first detector, second detector, arm, sliding mechanism, tilting mechanism, and control unit. The X-ray tube includes an anode to generate X-rays upon receiving electrons. The first detector has the first pixel size. The second detector has the second pixel size smaller than the first pixel size. The arm pivotally supports the X-ray tube, first detector, and second detector. The sliding mechanism slidably supports the first and second detectors so as to irradiate one of the first and second detectors with the X-rays generated by the X-ray tube. The tilting mechanism tiltably supports the X-ray tube to change the size of an effective X-ray focal spot on the anode. The control unit controls the sliding of the first and second detectors by the sliding mechanism upon interlocking with the tilting of the X-ray tube by the tilting mechanism.