An X-ray imaging device comprising: an X-ray source configured to emit X-rays to a portion of a field of view , wherein the portion of the field of view is less than a half of the field of view; and the field of view is a partial area of a head including a dental arch of a subject; an X-ray sensor configured to detect the X-rays that have passed through the portion of the field of view , wherein the X-ray sensor has a width less than a half of a cross-section length (w1) of the field of view , multiplied by a magnification ratio; a rotary arm configured to mount the X-ray source and the X-ray sensor such that the X-ray source and the X-ray sensor are disposed on both sides of the field of view to face each other; a rotary arm-moving unit configured to rotate the rotary arm around a rotary shaft between the X-ray source and the X-ray sensor and to move the rotary shaft on a plane perpendicular to the rotary shaft in at least a section of X-ray image obtaining; and an imaging processor configured to render a three-dimensional image of the field of view based on detection results of the X-rays detected by the X-ray sensor, wherein the rotary arm-moving unit is configured to rotate and move the rotary arm such that the X-ray source emits X-rays in position-specific directions to the portion of the field of view to satisfy that a range of angles of X-ray emissions in each position of the field of view is equal to or greater than a reference value and the imaging processor is configured to compensate for the X-ray detection results such that the range of angles of X-ray emissions at each position of the field of view is uniform, and render the three-dimensional image of the field of view based on the compensated X-ray detection results. an X-ray source configured to emit X-rays to a portion of a field of view , wherein the portion of the field of view is less than a half of the field of view; and the field of view is a partial area of a head including a dental arch of a subject; an X-ray sensor configured to detect the X-rays that have passed through the portion of the field of view , wherein the X-ray sensor has a width less than a half of a cross-section length (w1) of the field of view , multiplied by a magnification ratio; a rotary arm configured to mount the X-ray source and the X-ray sensor such that the X-ray source and the X-ray sensor are disposed on both sides of the field of view to face each other; a rotary arm-moving unit configured to rotate the rotary arm around a rotary shaft between the X-ray source and the X-ray sensor and to move the rotary shaft on a plane perpendicular to the rotary shaft in at least a section of X-ray image obtaining; and an imaging processor configured to render a three-dimensional image of the field of view based on detection results of the X-rays detected by the X-ray sensor, wherein the rotary arm-moving unit is configured to rotate and move the rotary arm such that the X-ray source emits X-rays in position-specific directions to the portion of the field of view to satisfy that a range of angles of X-ray emissions in each position of the field of view is equal to or greater than a reference value and the imaging processor is configured to compensate for the X-ray detection results such that the range of angles of X-ray emissions at each position of the field of view is uniform, and render the three-dimensional image of the field of view based on the compensated X-ray detection results. <EOS>