PROBLEM TO BE SOLVED: To provide an X-ray monochromator that not only can generate X rays of high luminance but also can cover a wide wavelength range only with a single monochromator crystal.
SOLUTION: In this manufacturing method, a base member that is cut out from a cylindrical body with a central axis at the maximum asymmetric angle α0 to the plane orthogonal to the central axis line is prepared. Subsequently, the asymmetrically cut face of the base member is shaped along the circumference of an imaginary cylindrical body with a radius R0 to form an asymmetric cut curve face. Then, a monochromator crystal is coupled on the asymmetrically cut curve face. Such a constitution makes it possible to simultaneously obtain an asymmetric angle α and a curvature radius R to a desired wavelength only by a rotary adjustment around the ϕ axis.