An X-ray CT photography apparatus comprising: an X-ray generator; an X-ray detector; a support part that includes an exterior part supporting said X-ray generator and said X-ray detector while said X-ray generator and said X-ray detector are opposed to each other and are accommodated therein; and a base that rotatably supports said support part such that said X-ray generator and said X-ray detector turn about a horizontal turning axis, wherein said exterior part includes a pair of arms (34, 36) and an arm base part, said pair of arms (34, 36) being connected to both ends of the arm base part, said pair of arms (34, 36) supported by said arm base part in a parallel state extending along said turning axis, said pair of arms (34, 36) and arm base part are formed into a continuous tubular U-shape, said support part includes a turning support shaft part that is fixed to said exterior part so as to extend onto an opposite side to said pair of arms (34, 36) along said turning axis, a generator-side opening, to which the X-ray generator is attached while accommodated therein, is formed in one of the pair of arms (34, 36), a detector-side opening, to which the X-ray detector is attached while accommodated therein, is formed in the other of the pair of arms (34, 36), and said base includes a seat and a turning support base part that rotatably supports said turning support shaft part above said seat to support said support part in a cantilever manner, characterized in that said X-ray CT apparatus further comprises: a cavity part being formed along said turning axis in said exterior part, an accommodation part that is accommodated in said cavity part and supported in a non-rotatable manner by an accommodation part support part which is fixed to said turning support base part while opened towards a space between said pair of arms (34, 36), at least part of a subject being able to be accommodated in said accommodation part, said exterior part being made of carbon fiber reinforced plastic. an X-ray generator; an X-ray detector; a support part that includes an exterior part supporting said X-ray generator and said X-ray detector while said X-ray generator and said X-ray detector are opposed to each other and are accommodated therein; and a base that rotatably supports said support part such that said X-ray generator and said X-ray detector turn about a horizontal turning axis, wherein said exterior part includes a pair of arms (34, 36) and an arm base part, said pair of arms (34, 36) being connected to both ends of the arm base part, said pair of arms (34, 36) supported by said arm base part in a parallel state extending along said turning axis, said pair of arms (34, 36) and arm base part are formed into a continuous tubular U-shape, said support part includes a turning support shaft part that is fixed to said exterior part so as to extend onto an opposite side to said pair of arms (34, 36) along said turning axis, a generator-side opening, to which the X-ray generator is attached while accommodated therein, is formed in one of the pair of arms (34, 36), a detector-side opening, to which the X-ray detector is attached while accommodated therein, is formed in the other of the pair of arms (34, 36), and said base includes a seat and a turning support base part that rotatably supports said turning support shaft part above said seat to support said support part in a cantilever manner, characterized in that said X-ray CT apparatus further comprises: a cavity part being formed along said turning axis in said exterior part, an accommodation part that is accommodated in said cavity part and supported in a non-rotatable manner by an accommodation part support part which is fixed to said turning support base part while opened towards a space between said pair of arms (34, 36), at least part of a subject being able to be accommodated in said accommodation part, said exterior part being made of carbon fiber reinforced plastic. a cavity part being formed along said turning axis in said exterior part, an accommodation part that is accommodated in said cavity part and supported in a non-rotatable manner by an accommodation part support part which is fixed to said turning support base part while opened towards a space between said pair of arms (34, 36), at least part of a subject being able to be accommodated in said accommodation part, said exterior part being made of carbon fiber reinforced plastic.