PROBLEM TO BE SOLVED: To provide an X-ray diagnostic apparatus which collects an image of a pre-stage detector excellent in resolution regardless of the size of a designated region of interest.SOLUTION: An X-ray diagnostic apparatus 1 includes: an X-ray source a post-stage detector a pre-stage detector the maximum visual field size of which is smaller than the maximum visual field size of the post-stage detector and which can detect X-rays at a stage more preceding than the post-stage detector and switch control means 138 which controls SID of the pre-stage detector according to a visual field size of the pre-stage detector corresponding to a designated region of interest when the region of interest is designated on an image by the post-stage detector.
