PROBLEM TO BE SOLVED: To provide an X-ray diffraction device and an X-ray diffraction system which is easily portable and handleable, having an inexpensive structure, and capable of imaging simply an image of a diffraction ring.
SOLUTION: When mounting parts 9, 10 are mounted on a rail 1, this X-ray diffraction device 5 is installed on the rail 1, and the incident angle ϕ0 of X-rays is set at a single-incident angle. The X-ray diffraction device 5 is stopped at an arbitrary measuring spot on the rail 1, and an X-ray irradiation point on the head top face 1d is irradiated with the X-ray generated by an X-ray generation device 3 from an X-ray irradiation part 6. As a result, the diffracted X-rays from the rail 1 enters an imaging plate 7a, and the whole image of the diffraction ring is imaged and recorded by the imaging plate 7a. Then, when the imaging plate 7a is dismounted from the X-ray diffraction device 5 and mounted on a reading device 11, image information of the diffraction ring is read from the imaging plate 7a, and the image information of the diffraction ring is analyzed by an evaluation device 12, to thereby evaluate the residual stresses or the like in the rail 1.