PROBLEM TO BE SOLVED: To provide an X-ray image diagnostic apparatus and an X-ray control method capable of following the movement of an operator's visual line and setting a region of interest to control the luminance for a proper value.SOLUTION: The X-ray image diagnostic apparatus 1 comprises a visual line detection sensor 15 for detecting an operator's visual line position relative to a displayed transillumination image, and sets the position of a ROI (region of interest), following the detected visual line position. The X-ray image diagnostic apparatus 1 then determines the feedback value of the X ray condition (X ray tube voltage) on the basis of the luminance value in the ROI to control the magnitude of irradiated X ray at the next timing. The X-ray image diagnostic apparatus can change the size and shape of the ROI on the basis of the movement quantity and movement speed of the operator's visual line. In addition, the X-ray image diagnostic apparatus may switch the feedback value calculation range between the visual line position and peripheral regions around the visual line position if a substance having a high X-ray absorption rate such as a metal is contained in the ROI.
