The EMG information is mainly used for the interface of powered prostheses. However, it is difficult to bend fingers to a specified angle like a human. In this paper, five fingers are selected from ten fingers of feet for operating powered prosthesis's fingers. This system is to operate each finger of powered prostheses by obtaining joint displacement information of the fingers of feet. The joint displacement information is obtained with the five bend sensors. This proposed method makes it possible to operate each finger of powered prostheses independently.