A presentation system with one 100 inch and two 60 inch TV monitors has been constructed for lectures. This system can take as its input printed matter, video, LD, CD, or pictures created on a personal computer. Materials such as textbooks, reference data, and educational videos are used for the experimental lectures. Questionnaires given to the students attending the experimental lectures revealed that most of the students considered the educational videos and reference data useful for understanding the lectures. However, principal component analysis of the evaluated data shows that the effect of the videos is independent of student' understanding of the entire lectures.