Abstract: The device is configured from: a reflective surface shape controllable mirror in which a band-shaped X-ray reflective surface 2 is formed on a central portion of a front surface of a substrate 1, reference planes 3 are formed along both sides of the X-ray reflective surface, and a plurality of piezoelectric elements 4 are attached to at least one of front and back surfaces of the substrate so as to be arranged in the longitudinal direction of the X-ray reflective surface on both side portions of the substrate, and a multichannel control system for applying a voltage to each of the piezoelectric elements.