In this research, we compare the group of companies that acquired during the period from April 2000 to March 2016 (treatment groups) and the group of companies that did not acquire during the same period (control group) to clarify the effect of improving the profitability expected. In particular, as a measure to effectively utilize acquisitions strategically by Japanese companies, we analyze to “Acquiring a wholly-owned subsidiary”, “Acquiring an unlisted company”, “Acquisition by management deteriorating company whose low internal reserve ratio was indicated before the acquisition” and “the effect of introducing business combination accounting”. As a result, the profitability improvement effect of acquisitions was demonstrated in terms of current asset turnover rate in common with all samples, takeover into a wholly-owned subsidiary, acquisition for unlisted companies, and acquisitions by management deteriorating companies, but on the other hand, significant differences were appeared on the ratio of ordinary profit to total capital, the ratio of net income to total capital and financial leverage. However, in acquisitions by management deteriorating companies, profitability improvement effect was shown in capital efficiency, shareholder investment efficiency, sales efficiency and asset efficiency. The effect of introducing business combination accounting on the profitability improvement effect of the acquisition did not appear.