For example, for the prevention of the fall down, new technologies are required to obtain information related to humans. Many methods are used for detection of human body movement. However, because the human body is complicated, the measurement of many points is necessary to express the movement of the human body. Many sensors are necessary, and therefore time and costs increase to measure many points. Therefore we made human walking simple as possible and tried to express it. The movement of an arm and foot are linked to the movement of a pendulum. The simple pendulum model was useful to express a rhythm of the movement of the human.