Magnetic materials are used in a variety of fields: magnetic disk devices that store big data, measuring devices for magnetic fields in the human body to examine the function of the human heart, power electronics for electric vehicles and motors. In our laboratory, we research the magnetic materials of them by using computer-based numerical simulations to analyze magnetic properties at the atomic level, magnetic behaviors at the submicron level called micromagnetics, and magnetic fields analysis using Maxwell’s equations. We also study analysis methods for supercomputers and quantum computers.