The growth of communication network technology enables people to take part in a distant lecture. We are developing a supporting system for a distant lecture named ACE (Automatic Camera control system for Education). The previous version of ACE captures the lecture focusing on the latest object written on a blackboard because a teacher frequently explains it. However, a teacher not always explains the latest object. We have designed, therefore, ACE to take a suitable shot according to a teacher's behavior. This paper describes our system, our camera control strategy, the algorithm to estimate a teacher's behavior in a lecture and experiment of our system.