Provided is an X-ray imaging device and a driving method thereof, the X-ray imaging device including an electron beam generation unit including a plurality of nano-emitters and a cathode, a first focusing electrode configured to focus an electron beam emitted from the electron beam generation unit, a deflector configured to deflect the electron beam focused by the first focusing electrode, a limited electrode configured to limit traveling of the electron beam deflected by the deflector, and an anode configured to be irradiated with the electron beam to emit an X-ray, wherein the limited electrode includes a limited aperture which the electron beam pass.