The purpose of this study is to find an effective solution to the status quo, children cannot concentrate on the class and behave irrationally; they are emotionally unstable and sometimes interrupt the class and even go away from the class. This is the case recently seen in the many primary schools in Japan. To solve this issue, the author, a teacher in a public primary school, found out an effective impact caused by the physical activities, called GO/NO-GO task, in order to investigate prefrontal cortex development in Japanese children through two types of exercises before classes. As a result, a faster response time and higher accuracy rate for GO/NO-GO tasks were observed. Based on this, since the accuracy rate after the two types of exercises in this study were significantly higher than those after the control activity and reading, it is suggested that two types of exercises were effective in improving inhibitory function.