[Problem] To provide an insertion device having a bending mechanism, wherein the device is capable of suppressing surface temperature when bending and of reducing cost of materials, has a strong bending force, is easy to control bending angle thereof and thus able to prevent overheating, and can have a small diameter. [Solution] A shape memory alloy contracting wire (12) is disposed outside a flexible inner tube (11) along a longitudinal direction of the inner tube (11). The contracting wire (12) is provided such that when electrically heated the wire contracts in length and curves the inner tube (11). A limiting member (13) is provided abutting a side face of the contracting wire (12) opposite the inner tube (11) so as to bend with the inner tube (11) along the curve of the inner tube (11). An outer tube (14) is provided so as to accommodate the inner tube (11), the contracting wire (12), and the limiting member (13) therein. The outer tube (14) is disposed spaced between an inner face and the contracting wire (12).
