An X-ray CT photographic apparatus (1, 1A), comprising: an X-ray generator that is configured to generate an X-ray; an X-ray regulating unit (13, 13a, 13A) that is configured to regulate an irradiation range of said X-ray generated from said X-ray generator and to shape said X-ray into an X-ray cone beam; an X-ray regulating controller that is configured to control said irradiation range of said X-ray by controlling said X-ray regulating unit (13, 13a, 13A); an X-ray detector (21, 21a, 21A) that is configured to detect said X-ray cone beam transmitted through a subject (M1, M2) on a detection surface; a read region controller that is configured to change a read region, where an X-ray detection signal of said X-ray cone beam is read in said X-ray detector (21, 21a, 21A), according to said irradiation range of said X-ray cone beam; a support body (30, 30A) that supports said X-ray generator and said X-ray detector (21, 21a, 21A) while said X-ray generator and said X-ray detector (21, 21a, 21A) are opposed to each other with said subject (M1, M2) therebetween; a support body turning drive unit (37, 37a) that is configured to turn said support body (30, 30A) about a turning shaft and to turn said X-ray generator and said X-ray detector (21, 21a, 21A) about said subject (M1, M2) during X-ray photography; and a CT photographic region setting unit (200, 200A to 200D, 300) that is configured to receive a setting manipulation of a CT photographic region being a target of an X-ray CT photography in said subject (M1, M2), wherein, assuming that a z-axis direction is an axis direction of said turning shaft, that an x-axis direction and a y-axis direction are two directions orthogonal to each other on a two-dimensional plane orthogonal to said z-axis direction, and that the y-axis direction is a direction from said X-ray generator toward said X-ray detector (21, 21a, 21A) in said x-axis direction and y-axis direction, said X-ray regulating controller is configured to change the irradiation range of said X-ray cone beam to said x-axis direction during said X-ray CT photography such that only a setting CT photographic region (CA, CAa to CAd) is irradiated with said X-ray cone beam according to said setting CT photographic region (CA, CAa to CAd) input through said CT photographic region setting unit (200, 200A to 200D, 300), and said read region controller is configured to change said read region with respect to said x-axis direction in said detection surface during said X-ray CT photography. an X-ray generator that is configured to generate an X-ray; an X-ray regulating unit (13, 13a, 13A) that is configured to regulate an irradiation range of said X-ray generated from said X-ray generator and to shape said X-ray into an X-ray cone beam; an X-ray regulating controller that is configured to control said irradiation range of said X-ray by controlling said X-ray regulating unit (13, 13a, 13A); an X-ray detector (21, 21a, 21A) that is configured to detect said X-ray cone beam transmitted through a subject (M1, M2) on a detection surface; a read region controller that is configured to change a read region, where an X-ray detection signal of said X-ray cone beam is read in said X-ray detector (21, 21a, 21A), according to said irradiation range of said X-ray cone beam; a support body (30, 30A) that supports said X-ray generator and said X-ray detector (21, 21a, 21A) while said X-ray generator and said X-ray detector (21, 21a, 21A) are opposed to each other with said subject (M1, M2) therebetween; a support body turning drive unit (37, 37a) that is configured to turn said support body (30, 30A) about a turning shaft and to turn said X-ray generator and said X-ray detector (21, 21a, 21A) about said subject (M1, M2) during X-ray photography; and a CT photographic region setting unit (200, 200A to 200D, 300) that is configured to receive a setting manipulation of a CT photographic region being a target of an X-ray CT photography in said subject (M1, M2), wherein, assuming that a z-axis direction is an axis direction of said turning shaft, that an x-axis direction and a y-axis direction are two directions orthogonal to each other on a two-dimensional plane orthogonal to said z-axis direction, and that the y-axis direction is a direction from said X-ray generator toward said X-ray detector (21, 21a, 21A) in said x-axis direction and y-axis direction, said X-ray regulating controller is configured to change the irradiation range of said X-ray cone beam to said x-axis direction during said X-ray CT photography such that only a setting CT photographic region (CA, CAa to CAd) is irradiated with said X-ray cone beam according to said setting CT photographic region (CA, CAa to CAd) input through said CT photographic region setting unit (200, 200A to 200D, 300), and said read region controller is configured to change said read region with respect to said x-axis direction in said detection surface during said X-ray CT photography.