This paper focuses on the Clearance dimensions based on the non-contact spatial area of the body movement, which a person composes consciously or unconsciously around his body by natural movement to his own purposes and aims in daily life. In particular, architectural investigations from the point of view of ergonomics are carried out in this paper about the relationship between an overhead clearance dimension necessary for going up and down the stars by walkers and its ceiling height. From the results through three experiments, it was verified that the adoption of results in going down is valid for setting the ceiling height in going up and down the stairs and a fixed overhead clearance dimension is necessary.