This paper examines the facts and significance of the special support senior high school. This is mainly based on results of the survey on special support schools, which only have the senior-highdepartment, for the students with intellectual disabilities, (following "special support senior high school" ), It is a desirable tendency that new special support senior high schools are founded, but it is not always happy without enough studies. As a method, I try the clarification of the significance of the special support senior high school in the whole upper secondary education through the result of a survey I did. As the progress of the special support senior high school, the special support senior high school which was only 1.0% existence in 1979 reached 5.1% in 2007. The survey made them clear that approximately 70% students are beyond the school criteria for school attendance and that 94% special support senior high schools are carrying out "carrier education". In detail, it became clear that the severe schools about the selection spend much more time for the carrier education than gentle school about the selection. The utility of the special support senior high school is clear to solve the congestion of the special support school. But there are many aspects to need examination, for example selection system and course of study. A non-degree graduate program and the sheltered employment system are also demanded. In conclusion, the large enlargement of the special support senior high school which does not lose the logic of the education is necessary. We want to emphasize that it should depend on the logic of the education to make the contents of the school, though we accept the administrative logic when we make hardware.