High spatial resolution, micrometer range, X-ray CT system has been developed at SPring-8. The experiments were performed at the undulator beam line BL47XU. An ''in-vacuum type'' undulator is employed as an X-ray source, and the X-rays are monochromatized with a liquid nitrogen cooled Si(111) double crystal monochromator. High precision rotation stage with air bearing was used for sample rotation. The transmitted images were obtained with a two-dimensional image detector, which consists of a single crystal phosphor screen (Lu 2 SiO 5 :Ce), an objective lens and a cooled CCD camera. In this system the smallest effective pixel size was set to 0.5μmx0.5μm. As a result of the experiments, three-dimensional images of a few micrometer-order texture has been successfully obtained with the developed CT system.