To provide a method for controlling an X-ray image diagnostic apparatus and an X-ray generation device equipped with an ABS system tracking movement of an object position without an operator performing setting operation for a region of interest (ROI), the determination condition storage unit (6i) storing ROI position determination conditions in which image statistical information is used for defining conditions to determine a position of an ROI in an X-ray image out of plural blocks generated by dividing the X-ray image into plural regions, the first block statistical information calculation unit (6f) calculating the image statistical information for each of plural blocks, and the region-of-interest position selection unit (6g) selecting a block that serves as an ROI from among plural blocks using the ROI position determination conditions and the image statistical information of each block are provided. A feedback value to be used in controlling the brightness value of the ROI is calculated based on the brightness value of the ROI, and irradiation conditions are determined so that the feedback value reaches a target brightness value.