This paper focuses on peer-reviewing classrooms, which is a helpful activity for teachers to improve teaching skills, involving students in their course, and using chalks and slides better. This kind of activities mainly consists of a lecture that is open to other teachers and a reflective discussion with the teachers after the lecture. In order to encourage such activities and make them more fruitful, we introduced an eye-tracking technique to understand visual attention of the experts on the actual classroom observations. Beginners on classroom observations are also measured and compared with the experts. From the results of the experiments, a trend of comparative gaze on the elements in classroom like the teacher, the slides, and the students is typically found among the experts. Peer-reviewing with recorded video files from four angles is also being evaluated. These trends may be applied to training programs in faculty development.