Provided is an intraoral X-ray imaging apparatus for detecting X-ray outside an oral cavity, including: a frame an X-ray irradiator which is installed to be supported by the frame and of which the one end portion is inserted into the oral cavity and which irradiates X-ray through an X-ray irradiation hole formed on the one end portion inserted into the oral cavity and an X-ray detector which is arranged to be separated from the X-ray irradiator in the frame so as to detect the X-ray irradiated from the X-ray irradiator outside the oral cavity and which is movably installed so as to adjust a distance to the X-ray irradiator.