An X-ray CT imaging apparatus, comprising: a frame a first supporter having a rotary shaft, the first supporter supporting an X-ray generator for generating an X-ray cone beam and a two-dimensional X-ray detector for detecting the X-ray cone beam, the X-ray generator and the X-ray detector being arranged to interpose an object: an object holder for supporting the object; a motor for rotating the first supporter about the rotary shaft to move the X-ray generator and the X-ray detector around the object; a first movement mechanism mounted in the frame for moving the rotary shaft in a first direction perpendicular to the rotary shaft; a second movement mechanism for moving the object holder in a second direction perpendicular to the rotary shaft and crossing the first direction; and a controller for driving and controlling the motor and the first and second movement mechanisms in order to rotate the first supporter and in order to move at the same time the rotary shaft in the first direction by the first movement mechanism and the object holder in the second direction by the second movement mechanism; such that the rotary shaft travels along a circular orbit around a center (x) of an imaging region according to a rotational angle of the first supporter; the X-ray cone beam from the X-ray generator is transmitted through a part of the imaging region and then detected by the X-ray detector for an offset scan CT imaging of the object; and the circular orbit along which the rotary shaft travels is set so that the center axis of the X-ray cone beam enters the imaging region offset from the center (x) of the imaging region. a frame a first supporter having a rotary shaft, the first supporter supporting an X-ray generator for generating an X-ray cone beam and a two-dimensional X-ray detector for detecting the X-ray cone beam, the X-ray generator and the X-ray detector being arranged to interpose an object: an object holder for supporting the object; a motor for rotating the first supporter about the rotary shaft to move the X-ray generator and the X-ray detector around the object; a first movement mechanism mounted in the frame for moving the rotary shaft in a first direction perpendicular to the rotary shaft; a second movement mechanism for moving the object holder in a second direction perpendicular to the rotary shaft and crossing the first direction; and a controller for driving and controlling the motor and the first and second movement mechanisms in order to rotate the first supporter and in order to move at the same time the rotary shaft in the first direction by the first movement mechanism and the object holder in the second direction by the second movement mechanism; such that the rotary shaft travels along a circular orbit around a center (x) of an imaging region according to a rotational angle of the first supporter; the X-ray cone beam from the X-ray generator is transmitted through a part of the imaging region and then detected by the X-ray detector for an offset scan CT imaging of the object; and the circular orbit along which the rotary shaft travels is set so that the center axis of the X-ray cone beam enters the imaging region offset from the center (x) of the imaging region.