In this paper, I would like to consider, both practically and theoretically, the particular Japanese development of art brut/outsider art. First, I will examine the original meaning of the terms "art brut"/"outsider art" and review when and how they were introduced in Japan and were recognised by Japanese people. Next, I will focus on the activities of a social welfare institution, atelier incurve, located in south Osaka. The atelier does not use the term "outsider" to describe its own creative activities, even though it initially identified itself as producing "outsider art."