In order to study the acoustical problem in open-plan type schools, the relationship between space planning and sound environment was investigated for three open-plan type elementary schools. Acoustical conditions of classrooms were measured by sound propagation property between classrooms and sound level during class activities. Besides, questionnaire survey on teachers and children and inquiring survey on teachers were performed. From the results, it was confirmed that the lack of acoustical design worsens the sound environment of classrooms and induces the restriction of space use.