In this study, the effectiveness of the context-based approach in elementary science lessons was explored. In order to reveal the characteristics of Japanese elementary science lessons in terms of the use of the context-based approach, Japanese lessons (N=12) were compared with American lessons (N=10). It was found that the degree to which context-based approach is incorporated in elementary science lessons is smaller in Japan than in USA. Also, it was found that Japanese lessons tend to incorporate connections to everyday life only at the beginning of the lesson. Based on these findings, we developed a science lesson that incorporates story-based context throughout the lesson, and implemented it for a group of perspective science teachers (N=11). Through the results of a survey and interview, three important points to make the context-based approach effective were identified: 1) use of story-based context, 2) use of teaching materials that show the real image, and 3) importance of the clear experimental results performed during the lesson. A discussion to connect the findings to active learning follows.