The general characteristics of the colon are proposed in the mechanical point of view. This is prerequisite information when we want to develop endoscopic robot which can move well in the human colon. Friction property which comprise static and dynamic friction coefficient is investigated. The elastic property of colon is also investigated: the radial tensile force is measured in the elastic range. The effect on the robot is revealed by using experimental method. The design parameters of the robot are then investigated: one is for the moving mechanism which has to be selected in view of mobility compared to the above knowledge. The other is for selection problem on the fin type and size in the inverse screw type. Several apparatus for friction property measurements were made and carefully made experiments. The resulting data were analyzed. Final results show that inverse screw type of robot has more mobility compared to the rotational inertia type.