[Problem] To provide a dental oral X-ray photography device that obtains three-dimensional X-ray image.[Solution] At the time of photographing with a use of an X-ray device, a retention substrate which is retained by occlusion is provided. A light receiver holding portion that is disposed on an end portion of a part of the retention substrate which is inserted in an oral cavity and that holds an X-ray receiving portion is provided. A second guide portion which is disposed at a position opposed to the light receiver holding portion with the retention substrate sandwiched therebetween, and is used to position a second X-ray device including a first X-ray source and a second X-ray source so that the first X-ray source is disposed at a first position separated by a second distance from a reference line and separated by a first distance from an image taking surface when viewed from above the retention substrate, and the second X-ray source is disposed at a second position which is line symmetric to the first position with the reference line set as an axis of symmetry. A first guide portion and the second guide portion are held by the retention substrate in a state of being replaceable by attaching or detaching from the retention substrate.La présente invention vise à fournir un dispositif de radiographie qui permettrait dobtenir une radiographie en 3D.Linvention concerne par conséquent un substrat de retenue qui est retenu par occlusion, fourni au moment de prendre une radiographie. Linvention concerne en outre une partie de retenue de récepteur optique qui est disposée sur une partie dextrémité dune partie du substrat de retenue qui est insérée dans une cavité buccale et qui maintient une partie de réception de rayons X. Une seconde partie de guidage qui est disposée à une position opposée à la partie de retenue du récepteur optique avec le substrat de retenue pris en sandwich entre celles-ci, et est utilisé pour positionner un second dispositif à rayons X comprenant un
