A sample sealing vessel 8 includes a plurality of wall faces comprising a material for transmitting X-ray, an X-ray source 1 is arranged at a wall face 11 to irradiate primary X-ray, a face 12 different from the face irradiated with the primary X-ray is arranged to be opposed to an X-ray detector 10, and the primary X-ray from the X-ray source 1 is arranged to be able to irradiate the wall face 12 of the sample sealing vessel to which the X-ray detector 10 is opposed.