There is provided a nondestructive method for inspecting ceramic structures, the method which not only easily detects the position and size of an internal defect in a ceramic structure in a short time, but also accurately identifies the position, shape, and size of the internal defect. In the method, the distribution of X-ray absorption coefficients (CT numbers) at fault planes of the ceramic structure is measured by irradiating the periphery of the ceramic structure with X rays along the periphery of the ceramic structure so that the X rays scan the entire periphery. The X rays are emitted from an X-ray tube at a tube voltage in the range of 80 to 400 kV and a tube current in the range of 2 to 400 mA.