In this paper, we present a soundtrack generation system that can automatically add a soundtrack with the length and climax points aligned to those of a video clip. Adding a soundtrack to a video clip is an important process in video editing. Editors tend to add chorus sections to the climax points of the video clip by replacing and concatenating musical segments. However, this process is time-consuming. Our system automatically detects climaxes of both the video clips and music based on feature extraction and analysis. This enables the system to add a soundtrack in which the climax is synchronized to the climax of the video clip. We evaluated the generated soundtracks through a subjective evaluation.