An X-ray fluoroscopic imaging apparatus controls movement of shield plates so that a length of a first pre-image in an x direction is larger than a length of a strip image. A capturing position of the first pre-image is adjusted so that an upper end of the first pre-image matches an upper end of a capturing range of a long image. Thus, where a long region is set on the basis of the first pre-image at present, it is possible to check whether a desired X-ray image is included in a strip image. It is possible to correct a position of an imaging system to an appropriate position as an imaging start point by referring to an X-ray image included in the first pre-image having a large amount of information. Therefore, it is possible to acquire a long image appropriate for diagnosis through slot imaging using this apparatus.
