Mitsubishi Steel Mfg. Co., Ltd. engages in the manufacture and sale of special steels, springs, casting and forging materials, and machinery. It operates through the following segments: Special Steel Bars, Springs, Formed & Fabricated Products, Machinery, and Others. The Special Steel Bars segment handles the manufacture and sale of steel bars that includes machine structural alloy steel, carbon steel for machine structural use, springs, tools, and bearing steel. The Springs segment includes coils, leaf, and precision springs, press assembly, built-in antenna, and shoe plate for rubber pads. The Formed & Fabricated Products segment covers the manufacture and sale of steel and precision casting, precision machined component, general forging, alloy materials, permanent magnet, magnet application components, and special alloy and fine powder. The Machinery segment manufactures and sells press machines, general, industrial and plant machinery, environmental equipment, and magnetic separators. The Others segment includes the distribution and service business. The company was founded in April 1917 and is headquartered in Tokyo, Japan.