A method and apparatus of acquiring a plurality of focal spots for X-rays. The method includes radiating an electron beam from a cathode of a magnetic field generating apparatus toward a movable anode of the magnetic field generating apparatus, and irradiating a target with an X-ray that is produced from the radiated electron beam by the anode. The anode comprises an inclined side in which a part of the inclined side protrudes, and the plurality of focal spots for X-rays are acquired based on the radiated electron beam and the inclined side.
