Abstract: A bending mechanism for use with a stereoscope, comprises a tubular body or linear body having a bending part, a movable part which can move in the lengthwise direction of the tubular body or linear body, two actuators formed to act in opposition to each other via the movable part, and a pull wire which extends in the lengthwise direction along the bending part. One end of the wire is fixed to one end side of the bending part and the other end of the wire is fixed to the movable part set at the other end side of the bending part. At least one of the two actuators is a shape memory element. The bending mechanism of the present invention is free from displacement of the movable part when bending action is not needed, since the two actuators are used which act in opposition to each other via the movable part, and thus, buckling of the bending part can be prevented. The simple structure of the activator unit of the present invention facilitates a reduction of the size of the structure.