This X-ray diagnostic apparatus (1) is provided with: an imaging unit (40) for rotatably holding an X-ray tube (3) and an X-ray detector (7) by means of a C arm (6), and generating X-ray image data relating to a subject under test； a display unit (12) for displaying X-ray images； an input unit (11) for inputting a target insertion location and a target destination location of a puncture needle to be inserted into the subject under test； a puncture needle extraction unit (212) for extracting the region of the puncture needle from an X-ray image； an imaging control unit (17) for controlling the imaging unit (40) in order to generate an X-ray image in which an imaging center line connecting the focal point of the X-ray tube (3) and the center location of the X-ray detection face of the X-ray detector (7) has a slope angle of less than 90 degrees with respect to a guide line connecting the target insertion location and the target destination location； an inserted length calculation unit (213) for identifying the apparent length of the puncture needle on the basis of the region of the puncture needle extracted from an X-ray image having a slope angle of less than 90 degrees, and calculating an estimated inserted length of the puncture needle inserted into the test subject, on the basis of the apparent length of the puncture needle and the slope angle； and a notification unit (20) for notifying the user of assisting information for assisting the operation to insert the puncture needle.La présente invention concerne un appareil de diagnostic à rayons X (1) qui est équipé : d'une unité d'imagerie (40) pour maintenir de manière pivotante un tube à rayons X (3) et un détecteur de rayons X (7) au moyen d'un arceau (6), et générer des données de radiographie liées au sujet en cours d'examen ； d'une unité d'affichage (12) pour afficher des radiographies ； d'une unité d'entrée (11) pour entrer un emplacement d'insertion cible et un emplacement de destination cible d'une aiguille
