Researches on the introduction of ERP system kept on examining the critical successful factors (CSFs) that focus on factors to achieve effectively successful projects, and trying to measuring the actual effectiveness of the introduction of ERP system. However, most of the preceding researches on the effectiveness of the introduction of ERP system that was searching devoted effects has been ceased, and actually even researches on the economical results have just done the basic cognitive evaluation of result indicators by many questionnaires instead of objective measuring values, because of the difficulty of measuring the evaluation of the result. Moreover, researches on positive effects of the introduction of ERP on enterprise results and researches that failed to give advantageous effects showed different results each other. And a part of researches reported that only a part of result indicators were partially affected. In this research, we investigated Korean large enterprises or middle-sized enterprises in manufacture industry that introduces SAP R/3 and Oracle package to compare their quantitative financial results after the introduction of ERP system, in order to measure the effects of the ERP system. First, we evaluated the difference of the quantitative financial results before and after the introduction of the ERP system. Second, we evaluated the opportunities shown by the effects after the introduction of the ERP system. Third, we removed the sample of the exchange crisis (IMF) and executed the additional analysis to reflect the average increasing and decreasing rate in the industry, so that pure evaluation can be achieved. Inherent limits of precedent researches are removed and practical effects of the pure introduction of the ERP system are evaluated, so the research of this research is significant. The result of this research is as follows. Because of the introduction of ERP, the rate of turnover of inventory property has increased and sales of preparation inventory property have decreased so that more effective inventory property management has been achieved. Moreover, preparation sales of labor costs and preparation sales of the number of employees have decreased to show the effect of the reduction of labor costs. However, it could no be concluded that we could increase the profit due to the introduction of ERP system. Due to the introduction of ERP, although we concluded that the return on assets (ROA) and the additional value of one-person employee statistically showed obvious differences and increased, the return on equity failed to show obvious differences after the process of introduction of ERP.