An X-ray photography apparatus comprising: a support that supports an X-ray generator and an X-ray detector while said X-ray generator and said X-ray detector are opposed to each other, so that a head of a subject to be photographed being interposed therebetween, a subject retention part adapted to fix the head or a chin of the head of the subject, said X-ray detector is configured to output an electric signal according to an intensity of an incident X-ray, in order to provide an extraoral radiography; a moving mechanism that includes a turning part and a moving part, the turning part is configured to relatively turn said X-ray generator and said X-ray detector about said head by turning said support relatively to said head about a predetermined turning axis, the moving part is configured to relatively move said support to said head in a direction perpendicular to said turning axis; said moving mechanism is adapted to drive said support such that the extraoral radiography of a pseudo intraoral radiography region is provided in the way of tomography as a pseudo intraoral radiography, wherein the pseudo intraoral radiography region is a region equivalent to an imaging region of a conventional intraoral radiography, an image processor that is configured to generate a tomographic image (Ti1, Ti2, Ti11, Ti12), related to a specific tomographic plane, from projection images (IP1, IP2, IP3) of the X-ray based on said electric signal output from said X-ray detector; a photographic region designation receiving part that is configured to receive an operation to designate said pseudo intraoral radiography region including a row of teeth or part of a gum as said pseudo intraoral radiography region; and a controller that is configured to perform said pseudo intraoral radiography to said pseudo intraoral radiography region in which designation is received by said photographic region designation receiving part by said moving mechanism to adjust the position of said support, the X-ray generator is configured to irradiate said pseudo intraoral radiography region with the X-ray, said image processor is configured to perform different methods of image processing to X-ray image data obtained by said extraoral radiography of said pseudo intraoral radiography region, and to generate a plurality of tomographic images (Ti1, Ti2) from said projection images (IP1, IP2, IP3) obtained by said pseudo intraoral radiography, in which information content of an X-ray absorption related to X-ray absorption of an object existing before and behind said specific tomographic plane differ from each other. a support that supports an X-ray generator and an X-ray detector while said X-ray generator and said X-ray detector are opposed to each other, so that a head of a subject to be photographed being interposed therebetween, a subject retention part adapted to fix the head or a chin of the head of the subject, said X-ray detector is configured to output an electric signal according to an intensity of an incident X-ray, in order to provide an extraoral radiography; a moving mechanism that includes a turning part and a moving part, the turning part is configured to relatively turn said X-ray generator and said X-ray detector about said head by turning said support relatively to said head about a predetermined turning axis, the moving part is configured to relatively move said support to said head in a direction perpendicular to said turning axis; said moving mechanism is adapted to drive said support such that the extraoral radiography of a pseudo intraoral radiography region is provided in the way of tomography as a pseudo intraoral radiography, wherein the pseudo intraoral radiography region is a region equivalent to an imaging region of a conventional intraoral radiography, an image processor that is configured to generate a tomographic image (Ti1, Ti2, Ti11, Ti12), related to a specific tomographic plane, from projection images (IP1, IP2, IP3) of the X-ray based on said electric signal output from said X-ray detector; a photographic region designation receiving part that is configured to receive an operation to designate said pseudo intraoral radiography region including a row of teeth or part of a gum as said pseudo intraoral radiography region; and a controller that is configured to perform said pseudo intraoral radiography to said pseudo intraoral radiography region in which designation is received by said photographic region designation receiving part by said moving mechanism to adjust the position of said support, the X-ray generator is configured to irradiate said pseudo intraoral radiography region with the X-ray, said image processor is configured to perform different methods of image processing to X-ray image data obtained by said extraoral radiography of said pseudo intraoral radiography region, and to generate a plurality of tomographic images (Ti1, Ti2) from said projection images (IP1, IP2, IP3) obtained by said pseudo intraoral radiography, in which information content of an X-ray absorption related to X-ray absorption of an object existing before and behind said specific tomographic plane differ from each other.