According to one embodiment, an X-ray diagnosis apparatus includes an X-ray generator, an X-ray diaphragm, an X-ray detector, an image capturing unit, a blood vessel running information acquiring unit, a device position specifying unit, and a diaphragm controller. The X-ray generator emits X-rays. The X-ray diaphragm restricts a region to be irradiated with X-rays emitted from the X-ray generator. The X-ray detector detects X-rays emitted from the X-ray generator. The image capturing unit acquires an X-ray image based on a detection result obtained by the X-ray detector. The blood vessel running information acquiring unit acquires blood vessel running information. The device position specifying unit specifies the position of a device in the X-ray image. The diaphragm controller controls the X-ray diaphragm based on the blood vessel running information and the position of the device.