An X-ray inspection device is adapted to detect foreign matter in a target object while the target object is conveyed. The X-ray inspection device includes an X-ray emission device, a scintillator unit, a slit member and a photodiode array. The scintillator unit extends in a direction that intersects a conveyance direction of the target object, and is configured and arranged to optically convert the X-rays emitted by the X-ray emission device into visible light. The slit member forms a slit that extends in the direction that intersects the conveyance direction, and is disposed on an upstream side of the scintillator unit with respect to a direction of X-ray irradiation. The slit member is arranged so that a width of the slit is narrower than a width of the scintillator unit, and is equal to or wider than half a light-receiving width of the photodiode array in the conveyance direction.