Teachers' misunderstanding the concept of inclusive education will not lead to good practices, rather make an exclusive environment for pupils with special educational needs in mainstream schools. This study clarified teachers' attitudes towards the image of inclusive education with conjoint analysis and cluster analysis. The participants for this study were 182 teachers who were from both mainstream schools and special schools. Their image about inclusive education was mainly dependent upon the organization of group and size of a group. The subfile summary of the conjoint analysis indicated that the teacher's views of inclusive education as images of "expanding school environment to include a child", withdrawal to "resource room", "small groups", and "a pupil with disability in a mainstream group." On the other hand, images of "repudiation of segregated learning opportunities", "homogeneous group", "a large size group", and "various attributes in a group" were perceived as "non-inclusive." The author has divided the participants into two groups by cluster analysis. The factors in dividing were discussed as not depend on their teaching experience nor school type, but local school environment - such as enrollment ratio of foreign pupils.