In “Living Environment Study’s” research, there has been a tendency that a teacher is not recognized as a main agent to design and practice “Living Environment Study’s” lesson because of its characteristic that values students and students’lives, which is the main content of “Living Environment Study.” In this case study, we problematize this research trend, and try to clarify the teacher’s role in “Living Environment Study” lesson design and practice. With this purpose, the research focuses on a teacher, who designed and practiced a unit called “Village Explore,” and describes and analyzes the teacher’s gatekeeping narrative. Firstly, we extract a theoretical framework to analyze a teacher’s gatekeeping narrative by reviewing literature on gatekeeping theory. The data, which comprises a unit plan, field notes, students’worksheets, focus group interview with three sample students, and a semi-structure interview with a teacher, were collected, and analyzed by open and axis coding. There are two main findings and implications of this study. One is to suggest a new research field in “Living Environment Study” by illuminating the fact that the teacher played a role as a gatekeeper “even in” “Living Environment Study.” The other is to clarify a uniqueness of “Living Environment Study’s” gatekeeping, which a teacher played roles of a gatekeeper, a guide, and a negotiator.