A medical X-ray photography apparatus, comprising: a support that supports an X-ray generator and an X-ray detector while the X-ray generator and the X-ray detector are opposed to each other and configured to have a subject interposed therebetween, wherein the X-ray generator is configured to emit an X-ray beam and the X-ray detector is configured to output an electric signal according to an intensity of a detected X-ray; a moving mechanism that includes a turning part and moving part, wherein the turning part is configured to turn said support about a turning shaft and the moving part is configured to move said support along a two-dimensional plane orthogonal to an axial direction of said turning shaft; a photographic region assignment receiving part that is configured to receive an operation to assign a part of a dental arch as a simulated intraoral radiography region; an image processor (8, 801) that is configured to generate an X-ray image by processing X-ray image data detected by said X-ray detector and adapted to reconstruct a tomographic image of a planar or curved cutting plane (Al, A2) set in accordance with the part of the dental arch assigned as the simulated intraoral radiography region; a control part that is configured to perform simulated intraoral radiography by reconstructing a tomographic image of the cutting plane of said simulated intraoral radiography region, which is a simlulated intraoral radiography image that is equivalent to a simple projection image, as obtained by with irradiating X-rays in one direction while a conventional X-ray film is mounted in the mouth cavity, of a photographic region of a conventional intraoral radiography, by controlling said moving mechanism based on a movement starting signal to move said support to a predetermined photography starting position together with setting a turning center of said turning shaft to move and turn said X-ray generator and said X-ray detector such that the simulated intraoral radiography region is irradiated in multiple directions by the X-ray beam; and a signal output switch that includes a movement starting signal output part configured to output said movement starting signal to said control part. a support that supports an X-ray generator and an X-ray detector while the X-ray generator and the X-ray detector are opposed to each other and configured to have a subject interposed therebetween, wherein the X-ray generator is configured to emit an X-ray beam and the X-ray detector is configured to output an electric signal according to an intensity of a detected X-ray; a moving mechanism that includes a turning part and moving part, wherein the turning part is configured to turn said support about a turning shaft and the moving part is configured to move said support along a two-dimensional plane orthogonal to an axial direction of said turning shaft; a photographic region assignment receiving part that is configured to receive an operation to assign a part of a dental arch as a simulated intraoral radiography region; an image processor (8, 801) that is configured to generate an X-ray image by processing X-ray image data detected by said X-ray detector and adapted to reconstruct a tomographic image of a planar or curved cutting plane (Al, A2) set in accordance with the part of the dental arch assigned as the simulated intraoral radiography region; a control part that is configured to perform simulated intraoral radiography by reconstructing a tomographic image of the cutting plane of said simulated intraoral radiography region, which is a simlulated intraoral radiography image that is equivalent to a simple projection image, as obtained by with irradiating X-rays in one direction while a conventional X-ray film is mounted in the mouth cavity, of a photographic region of a conventional intraoral radiography, by controlling said moving mechanism based on a movement starting signal to move said support to a predetermined photography starting position together with setting a turning center of said turning shaft to move and turn said X-ray generator and said X-ray detector such that the simulated intraoral radiography region is irradiated in multiple directions by the X-ray beam; and a signal output switch that includes a movement starting signal output part configured to output said movement starting signal to said control part.