Finger parts flex and extend about joint sections. A wire is arranged along each finger part through the joint sections. A motor winds the wires to pull the wires in the flexing direction and cause the finger parts to flex. A polymer actuator arranged to correspond to a part of each wire is formed in an elongated shape of a polymer material and elastically deforms in response to an application of voltage and performs extension and contraction in the axial direction by being restored to the original shape in response to stoppage of the voltage application. A lock mechanism restricts relative movement between the wire and the motor after the wire has been wound up by the motor. The polymer actuator performs extension and contraction while relative movement is restricted by the lock mechanism, thereby pulling the wire in the flexing direction.
