Abstract
In general, the straight type handrail has been installed on stairs. Recently, the wave type handrail also came to be installed. It can be more effective than a straight type handrail because there are the horizontal parts that support the body easily making a strong grip unnecessary. And, the vertical parts make easy to pull when walking up stairs. In gripping the handrail, the angle of the wrist receives the limitation, because straight and wave type handrail have the only angle in a plane parallel to the side walls. Therefore, it is not necessarily easy to grasp the handrail naturally. The spiral type handrail that can change the grasp angle in three dimensions was developed. The spiral handrail can be grasped with the natural angle. Moreover, it is possible to go up and down the stairs more comfortably, because, like the wave type handrail, there are horizontal and vertical parts.
