1. An X-ray diagnosis apparatus comprising: an image-data creating unit that creates X-ray images along a time sequence by detecting X-rays radiated from an X-ray tube and passed through a subject; a feature point detecting unit that detects a position of a feature point included in a certain object on a new image created by the image creating unit each time when the image creating unit creates new image as a new one of X-ray images along a time sequence; a correction-image creating unit that creates a correction image from the new image through at least one of image shift and image transformation, so as to match up the position of the feature point detected on the new image by the feature point detecting unit, with a reference position that is a position of a feature point already detected by the feature point detecting unit on a reference image that is a certain X-ray image created before the new image; and a display control unit that performs control of displaying newly created correction image as an image for display so as to be sequentially displayed as a moving image onto a certain display unit, each time when the correction-image creating unit newly creates the correction image along a time sequence.