The objective of the research was to build thestudent’s careness character of the environment through the utilization of learning forest prototype. This research was conducted in the even semester of the academic year 2017/2018. The research was conducted by using classroom action research that consists of three cyclesthrough the Lesson Study for Learning Community (LSLC) program. During the learning process, the students planted the plants, fertilize, irrigate, and take careof plants. In this research, the researchers collaborated with some observers. The observers observed the student’s activity by using the observation sheets of student’s careness character of the environment. The results of the research indicated that the score of each cycle was increased, with the average final score was 91.72. In the initial process, before implementing the research, the student’s careness character of the environment has not appeared.Moreover, the result of the first cycle was 89,00 (89 %).Hence, the increase of the first cycle to the second cycle was 2,81%, then the increase of the second cycle to the third cycle was3,35%. Based on the result, the researchers suggest the utilization of learning forest prototypes to increase the student’s careness character of the environment.