Computational materials science (CMS) based on density functional theory (DFT) has been playing an invaluable role for investigation of molecules and solids from quantum mechanical points of view in accordance with development of both the computatial methods and massively parallel computers. To tackle more realistic but computational very challenging systems, one needs to handle a wide range of computational methods, algorithms, and pallelization techniques, and integrate them as software package, and we consider that it is important to develop such a software package at hand in order to explore frontiers of CMS. Since 2000 we have been continuously developing a software package, OpenMX (Open source package for Material eXplorer), for large-scale electronic structure calculations based on DFT, norm-conserving pseudopotentials, and pseudo-atomic localized basis functions [1-3]. The software package is shared under the practice of the GNU General Public License (GPL), and used by researchers in Universities, institutes, and companies to investigate a wide variety of materials such as carbon-based materials, magnetic materials, and nanoscale conductors. The developers are also distributed in Japan, Korea, China, and Spain. We have been continuously studying toward the further development.