A X-ray scattering measurement device and measurement method can measure, with high resolution, the intensity of X-rays which have undergone small-angle scattering and diffraction with reflection geometry and can easily and accurately measure a microstructure on the surface of a sample. The X-ray scattering measurement device is suitable for microstructural measurement on the surface of a sample includes an X-ray source that generates an X-ray; a first mirror and a second mirror that continuously reflect the generated X-ray; a sample stage that supports the sample; and a two-dimensional detector that detects the X-ray scattered on the surface of the sample. The first mirror focuses the generated X-ray onto the two-dimensional detector within a plane parallel to the surface of the sample, and the second mirror focuses the X-ray reflected by the first mirror onto the surface of the sample within a plane perpendicular to the surface of the sample.