Ion exchange polymer membrane in the dehydrated state was found to exhibit bending upon a small applied voltage, although the investigations on the hydrated ion exchange polymer membrane bending behavior have been performed quite intensively for more than a decade for the purpose of producing a practical polymer actuator. Our investigation on the dehydrated ion exchange polymer membrane has revealed that its bending direction is perfectly controllable by the polarity control of applied voltage and the degree of its bending curvature is also almost completely determined by the control of duration time of voltage application on it, while the hydrated ion exchange polymer membranes lack of such properties. Furthermore, the longevity of dehydrated ion exchange polymer membrane sustaining such a highly controllable properties has been found quite longer than that of the hydrated ion exchange polymer membrane. (C) 2004 Elsevier B.V. All tights reserved.