In order to design a prosthesis, it is important to consider fitting between skin of the limb and the socket. The purpose of this study is to quantify the normal force between the skin of the lower limbs and an inner socket in the lower limb prosthesis. To measure normal pressure sensors were set on the inside of prosthesis socket. Pressure and stress were collected during static standing, stepping and running motions. Changes in the prostheses, inner sockets, and alignment were investigated based on the contact forces. It was found that the distribution of normal stress changed according to the motion: maintaining static posture and dynamical motion such as walking. The relation between slipping of the stamp and the normal stress in the static posture diddered from that in running.