An X-ray CT imaging apparatus, comprising: a frame; a rotary shaft, supported by the frame; a first movement mechanism provided between the frame and the rotary shaft to move the rotary shaft with respect to the frame in a plane perpendicular to the rotary shaft; a supporter supported at a lower side of the rotary shaft, said supporter having an X-ray generator for generating an X-ray cone beam and an X-ray detector for receiving the X-ray cone beam from the X-ray generator, the X-ray generator and the X-ray detector being spaced apart to oppose each other so that the X-ray cone beam from the X-ray generator is detected by the X-ray detector; a second movement mechanism (36, 38, 60r) provided in the frame or in the supporter to rotate the supporter around the rotary shaft about a longitudinal axis thereof; and a controller configured to simultaneously drive the first movement mechanism and the second movement mechanism (36, 38, 60r) to move the rotary shaft and rotate the supporter around the rotary shaft so that a two dimensional movement of the rotary shaft by the first movement mechanism and a rotational movement of the supporter around the rotary shaft by the second movement mechanism (36, 38, 60r) are combined with each other, which results in that the rotary shaft travels along a circular orbit around a center of a CT imaging region of an object positioned stationary between the X-ray generator and the X-ray detector in accordance with a rotational angle of the supporter while the X-ray cone beam is projected to a part of the CT imaging region with a symmetrical axis of the X-ray cone beam displaced from a central position of the CT imaging region to perform an offset scan X-ray CT imaging of the object. a frame; a rotary shaft, supported by the frame; a first movement mechanism provided between the frame and the rotary shaft to move the rotary shaft with respect to the frame in a plane perpendicular to the rotary shaft; a supporter supported at a lower side of the rotary shaft, said supporter having an X-ray generator for generating an X-ray cone beam and an X-ray detector for receiving the X-ray cone beam from the X-ray generator, the X-ray generator and the X-ray detector being spaced apart to oppose each other so that the X-ray cone beam from the X-ray generator is detected by the X-ray detector; a second movement mechanism (36, 38, 60r) provided in the frame or in the supporter to rotate the supporter around the rotary shaft about a longitudinal axis thereof; and a controller configured to simultaneously drive the first movement mechanism and the second movement mechanism (36, 38, 60r) to move the rotary shaft and rotate the supporter around the rotary shaft so that a two dimensional movement of the rotary shaft by the first movement mechanism and a rotational movement of the supporter around the rotary shaft by the second movement mechanism (36, 38, 60r) are combined with each other, which results in that the rotary shaft travels along a circular orbit around a center of a CT imaging region of an object positioned stationary between the X-ray generator and the X-ray detector in accordance with a rotational angle of the supporter while the X-ray cone beam is projected to a part of the CT imaging region with a symmetrical axis of the X-ray cone beam displaced from a central position of the CT imaging region to perform an offset scan X-ray CT imaging of the object.