RYOBI which was established in 1943 tackled the integrated production of die-casting from early time, and became a company of the first place of the industry by the introduction of the casting machines from Switzerland in 1957 and 1958. Further, for the stability of corporate management and the independence, the company advanced to the industries of small offset press, the door closer, and the fishing tackle etc. For the promotion of the diversification, the rate of the die-casting to profit of the company has become half mostly by 1980s. After the collapse of the 'bubble' economy, the rate of the diversification section fell as a result of the company-wide restructuring for the improvement in a profit. Now, the rate of the die-casting is 73.1%. However, this is not the return to the past state. The number of the automakers in which RYOBI trades increases from three companies in 1984 to ten or more in 2011 by the entry to a global market, such as America, Britain and china, and technical innovation of a die-casting section. We can estimate that the management of RYOBI is stable.