The purpose of this study is to analyze the real effects of accounting earnings attributes in Japanese financial markets. Previous studies show that useful accounting attributes optimize firm’s investment levels through alleviating asymmetric information. Biddle and Hilary (2006), however, do not find the effects in Japanese economy, and suggest that its reason is the alternative information-problem-mitigating mechanisms. For instance, main bank system can alleviate the effects of accounting information on investment. Nevertheless some researchers indicate that the financial intermediaries might not effective, and its importance shrinks after the 1990’s. Hence, not a trivial question is whether the real effects of EAs are observed in Japanese economy. Using long historical data of Japanese firms, I find that useful accounting information optimizes firm’s investment levels. Specifically, not all but most earnings attributes alleviate over-investment; Earnings volatility, persistence, predictability, accruals quality, and aggregated indicator. Meanwhile, they do not alleviate over/under-investment. In addition, smoothness does not have significant effects or does have the effects opposite from my expectation. In conclusion, the real effects can be observed even in Japanese economy.