A dental X-ray photographic apparatus in the oral cavity comprises a base board, a supporter, a first guide unit, and a second guide unit.The base board is supported by dental occlusion when X-ray photographic operation is performed.The supporter is set at the end part of the base board. The end part of the base board is inserted in the oral cavity when X-ray photographic operation is performed. The supporter supports an X-ray receiver that has an X-ray sensor.The first guide unit faces the supporter through the base board. The first guide unit is used for positioning a first X-ray apparatus including an X-ray source. The X-ray source is arranged on a reference line that passes through the center of an imaging surface of the X-ray receiver and that is perpendicular to the imaging surface, viewed from the upper side of the base board. A distance between the imaging surface and the X-ray source is a first distance.The second guide unit faces the supporter through the base board. The second guide unit is used for positioning a second X-ray apparatus including a first X-ray source and a second X-ray source. A distance between the reference line and the first X-ray source is a second distance, viewed from the upper side of the base board. A distance between the imaging surface and the first X-ray source is the first distance. A distance between the reference line and the second X-ray source is the second distance. A line that passes through a first position on which the first X-ray source is set and a second position on which the second X-ray source is set is perpendicular to the reference line.The first guide unit and the second guide unit are exchangeable each other, and one of the first guide unit and the second guide unit is supported by the base board.本發明之課題為:提供可取得立體之X射線影像的牙科用口腔內X射線照相裝置。為解決上述課題,本發明包含有:保持基板,在使用X射線裝置進行拍攝時,藉由咬合來加以固持;受光體固持部,設於保持基板之插入口腔內的部分之端部,用來固持X射線受光部;及第2導引部,隔著保持基板而設在與受光體固持部對向的位置,用來將包含第1X射線源與第2X射線源的第2X射線裝置定位成:從保持基板之上方看來,第1X射線源配置於距離基準線恰第2距離且距離拍攝面恰第1距離的
