The purpose of this study is to clarify how it is possible to understand the development of scientific knowledge in Japanese junior high school science textbooks from the viewpoint of "context" in "context-based approach". As a result of the textbook analysis, we conclude : (1) Due to the lack of context or a "focal event", learning development is not based on the "need to know", (2) there is a weakness in the relationship between the sections of the units within the textbook, (3) learning development does not necessarily start with the relationships between everyday life and society.