In this paper, we propose a segmentation method of continuous lecture speech into topics. A lecture includes several topics but it is difficult to judge their boundaries. To solve this problem, transcriptions obtained by spontaneous speech recognition of a lecture speech is associated with the textbook used in the lecture. This method showed high performance of the topic segmentation with an average of 93.7%. Incorporating this method, we constructed a system where we can view an interesting part of lecture videos, by specifying the chapters or sections as well as keywords.