We examine how information inflow into Yen / Dollar market affects foreign exchange rate volatility through the estimation of the GARCH with information variable model. Since information inflow cannot be ob-served directly, we contrive the two types of proxy from our Ultra-High-Frequency data set; the number of quotes and the number of headline news in a given time period. The ARCH effect in conditional variance equation can be reduced when we incorporate the information inflow proxies into the GARCH model. Our findings show the volatility pattern of Yen / Dollar rate might be partly generated by information inflow, especially by the number of quotes. This result provides empirical support for the mixture of distribution hypothesis.