In the case of the loud sound concert in the open-air stage in urban area, the sound that might trouble is often measured. There is a case where high-rise residences and offices are adjacent to the stage in the urban area. Shibaura Institute of Technology (SIT) was received the complaint from the neighbor when the campus festival was hold. This report shows the measuring result of the sound of the concert on the open-air stage in the campus festival. The sound of the concert in the open-air stage was measured for 3 days. The measuring objects were band performance, dance performance and 'Shibaya' band performance. The measuring points were 21 points around the campus. The center point was decided at the stage. The measuring times were 8 hours from 10 o'clock to 18 o'clock that the concert held. Each measuring point was measured 3 minutes. Analysis object defined the sound of the 'Shibaya' that the sound was larger than other performances. The 'Shibaya' is originality sound of open-air stage concert in the festival. This event is the final event in the campus festival. We measured that sound pressure level (LP) was 101 dB at the center, and the level of the measuring point was 90 dB where is the distance of 100 m from the center . The loud sound of the open-air stage concert in the campus festival had reached neighbor, in this area, the building could not be fenced.