1. An X-ray imaging apparatus comprising: an X-ray sensor unit configured to detect X-rays; and a control unit configured to control driving of the X-ray sensor unit, wherein the control unit performs alignment imaging for imaging a still image of a subject, the still image being used as a reference for alignment of the X-ray sensor unit, and the control unit performs main imaging for imaging a moving image of the subject after the alignment imaging, and wherein the alignment imaging and the main imaging are performed under a same driving condition of the X-ray sensor unit.