A bending drive member to bend a bending member is arranged to extend in the direction of length of an elongate tube having flexibility, and attached to near the distal end of the tube with the distal end of the bending drive member being restricted in its position. The bending member drive member comprises a shape memory member formed by bundling together a plurality of wire-like shape memory materials each having a length, that spans from the position of one end to the other end, reversibly changed upon heating/cooling. The length of the shape memory member is changed dependent on a drive signal from a unit with a capability of heating. A non-compressive coil sheath through which the bending drive member extends is fixed at a distal end thereof to the elongate tube while the proximal end of the coil sheath is a free end with respect to the elongate tube.