The effectiveness of early English education was investigated in this study to determine if English should be taught formally in Japanese public elementary schools. We administered English tests and questionnaires to 1466 elementary school students in 2004 and 2005. The results showed significant differences between the English-education-experienced and non-experienced students and indicated positive effects of early English education. Although we confirmed the effects, some researchers claim that the effects may diminish at the junior high school level. To examine the above claim, we conducted a proficiency test and gave questionnaires to the seventh-year students of two junior high schools in 2006. As most of the students of the two elementary schools, at which we had conducted our research for the previous two years, entered the two junior high schools, the results of our new research gave us follow-up data on how the English ability of these students changed. The results showed a significant difference between the English-education-experienced at elementary schools and non-experienced and also between the experienced outside of school and non-experienced. It was also found that early English education helps to enhance students' interest toward English and facilitates learning motivation toward English after entering junior high school. (Contains 13 figures and 5 tables.)