Material science is one of the key word to consider the modern society, and the structural and crystal physics gives a fundamental base for this field. Crystal has a regular arrangement of atoms. Some of structural phase transitions change physical properties of materials completely such like a transformation from a graphite to a diamond. Sometimes magnitude of such atomic shifts is only less than 0.1 Å Diffraction technique can detect such a small change and reveals the law in a microscopic world. It seems very special investigation, but these studies are the bases of technologies such like an electrical condenser, a silicon wafer of semiconductor, a smart device of memory card, an optical device, a memory metal, an actuator of robotics, and so on. We use varieties of equipments. X-ray machines in our laboratory are very unique and useful to study the nature of phase transition phenomena, and we are still continuing to develop new machines such like a low-background vacuum X-ray photographic equipment for detailed crystal structure analysis below 4K. We sometimes use an X-ray diffractometer at SPring-8, which is the largest synchrotron facility in the world, to carry out the frontier experiments. Furthermore, we have constructed a neutron 4-circle diffractometer at Japan Atomic Energy Agency at Tokai, and we are investigating the role of crystal and magnetic structures for the properties of materials.