Itokawa particles are the first regolith sample returned from an asteroid. A variety of information on surface processes on the asteroid was revealed by the initial analysis such as space weathering (Noguchi et al., 2011, Science), solar wind noble gas implantation (Nagao et al., 2011, Science), particle erosion by grain motion (Tsuchiyama et al., 2011, Science), and shock features (Nakamura et al., 2011, PNAS). However, detailed processes, which are responsible for the regolith features and their comprehensive understanding have not yet been established. In order to solve the above problems, we focus on micro- and nano-structures of Itokawa particle surfaces using FE-SEM/EDX in this proposed research because the surfaces are the interface between space environments and Itokawa solid materials. The surface structures are evaluated by comparing with particle surface structures formed by laboratory experiments of impact, mechanical erosion and sputtering by high-energy particles. 3D structures of the particles are also examined using SR-CT because this can give petrological and mineralogical information and judge whether or not observed surface objects are connected inside. After these non-destructive analyses, selected samples are further examined by TEM for space weathering or mass spectroscopy for noble gas implantation (rest of them is returned to JAXA without any further processing). Preliminary results by the initial analysis show that Itokawa particles have fresh and aged surfaces (Matsumoto et al., 2012, LPSC). The present research will reveal the aging processes and give comprehensive understanding of surface processes on the asteroid.