An intraoral sensor comprising: an image sensor including a light detection region; a fiber optical plate being disposed on the image sensor to cover the light detection region; a scintillator being disposed on the fiber optical plate; and a case containing the image sensor, the fiber optical plate, and the scintillator, wherein the fiber optical plate includes: a first main surface opposing the image sensor and having a polygonal shape, a second main surface opposing the scintillator and having a polygonal shape, and a plurality of lateral surfaces connecting an edge of the first main surface and an edge of the second main surface, wherein the edge of the second main surface includes a plurality of corner portions, and a plurality of side portions connecting the corner portions adjacent to each other; characterized in that: the scintillator is provided on the second main surface and the plurality of lateral surfaces in such a manner that the corner portions and the ridge portions constituted by the lateral surfaces adjacent to each other are exposed, and the scintillator is arranged to extend onto the plurality of lateral surfaces via the edge of the second main surface. an image sensor including a light detection region; a fiber optical plate being disposed on the image sensor to cover the light detection region; a scintillator being disposed on the fiber optical plate; and a case containing the image sensor, the fiber optical plate, and the scintillator, wherein the fiber optical plate includes: a first main surface opposing the image sensor and having a polygonal shape, a second main surface opposing the scintillator and having a polygonal shape, and a plurality of lateral surfaces connecting an edge of the first main surface and an edge of the second main surface, wherein the edge of the second main surface includes a plurality of corner portions, and a plurality of side portions connecting the corner portions adjacent to each other; characterized in that: the scintillator is provided on the second main surface and the plurality of lateral surfaces in such a manner that the corner portions and the ridge portions constituted by the lateral surfaces adjacent to each other are exposed, and the scintillator is arranged to extend onto the plurality of lateral surfaces via the edge of the second main surface. a first main surface opposing the image sensor and having a polygonal shape, a second main surface opposing the scintillator and having a polygonal shape, and a plurality of lateral surfaces connecting an edge of the first main surface and an edge of the second main surface, wherein the edge of the second main surface includes a plurality of corner portions, and a plurality of side portions connecting the corner portions adjacent to each other; characterized in that: the scintillator is provided on the second main surface and the plurality of lateral surfaces in such a manner that the corner portions and the ridge portions constituted by the lateral surfaces adjacent to each other are exposed, and the scintillator is arranged to extend onto the plurality of lateral surfaces via the edge of the second main surface. the scintillator is provided on the second main surface and the plurality of lateral surfaces in such a manner that the corner portions and the ridge portions constituted by the lateral surfaces adjacent to each other are exposed, and the scintillator is arranged to extend onto the plurality of lateral surfaces via the edge of the second main surface.