This paper describes a new theory of shock absorption for EPS and we propose a new form buffer bush equipped with rack shaft end. In conjunction with recent trends in vehicles getting downsized and lighter, it is necessary for the EPS to get downsized and lighter. To downsize the EPS reduce the diameter of a rack shaft and increase stress on the rack gear. In order to solve this issue, the authors examined the buffer bush to increase energy of shock absorption with spring and friction, and we propose the new form buffer bush. This enables to reduce the impact load in a steering end without enlarging the size of the buffer bush. The new profile of the buffer bush is cylinder form with grooves, and when compressed, the external diameter is expanded and friction is produced. As a result, the bush achieves the target of shock absorption.