Campus laboratory is a kind of social network. All the members there have similar common sense in the domain of that social network. Members learn knowledge by interaction. Group meeting or exchanging of personal experiences inspires the knowledge innovation. However, social networks face an issue that knowledge cannot be inherited efficiently, even by using Blogs or E-mails. Thus, this paper proposes a knowledge management system (KMS) for social network services: a case study on campus laboratory, in order to inherit experiences of learning efficiently by using knowledge management. Knowledge is not only stored but also used efficiently; we propose Importance Analysis (IA) function for helping knowledge learning. At last, we gave questionnaires for the testing of the proposed system by members in the laboratory, and used the result of the questionnaires indicate that the system is useful for knowledge learning in laboratory.