Abstract
This study investigates the effect of aging on the evaluation of the optimum diameter during pipe easiness to grasp by the rating scale method and the paired comparison method. The pipe diameters examined from 25mm to 50mm. The mean value of the optimum grasping diameter evaluated by college students was lager than that evaluated by elderly persons. The rank between maximum and minimum evaluate value (range) in the college student was higher than that in the elderly person. These characteristics were depends on the abundance of the image appeared at grasping and the sensitivity of the cutaneous sense of hand.
