Magnesium alloys are the lightest among practical metal materials, characterized by high specific strength and specific stiffness. They also possess excellent vibration damping and electromagnetic shielding properties, and are widely used for lightweighting automotive parts, in aerospace, and for electronic device casings (such as PCs, smartphones, and cameras). As for main processing methods, die casting, which forms from a molten state, is the most common, but thixomolding utilizing a semi-molten state, as well as warm forging, extrusion, and rolling, are also applied. While strict attention to fire risk is required during machining, and there is a challenge in the difficulty of plastic deformation at room temperature, their exceptional lightness makes them an important material for which demand is expected to expand for next-generation mobility and IoT devices.