1. An X-ray diagnostic apparatus, comprising: a bed including a movable table on which a subject to be examined is placed; an X-ray generating unit; an X-ray detection unit; a support which movably supports the X-ray generating unit and the X-ray detection unit; an X-ray application switch which triggers generation of X-rays from the X-ray generating unit; an operation unit for moving the X-ray generating unit and the X-ray detection unit; an image generating unit which generates an image on the basis of an output from the X-ray detection unit; a display unit which is placed near the bed and displays the image; a detection unit which detects an advance distance, an advance direction, and an axial rotation angle of a catheter or a guide wire during a simulation period; and a simulation image generating unit which generates a simulation image from stored data during the simulation period in response to operation of the X-ray application switch and operation of the operation unit, wherein the simulation image generating unit generates the simulation image from the stored data in accordance with the detected advance distance, the detected advance direction, and the detected axial rotation angle.