Flexural structure and half-finished product thereof

A half-finished product of a flexural structure in which a multi-structured flexible body is bendable from an extended state to a flexed state, the half-finished product of the flexural structure comprising:

• an outer coil spring, constituting the multi-structured flexible body;
• an inner coil spring, provided inside the outer coil spring and having a wire overlap a wire of the outer coil spring in a non-close-contact state in a coil radial direction to constitute the multi-structured flexible body;
• and
• a one-side receiving member, receiving one side of the multi-structured flexible body,
• wherein when assembled to a device side, a close-contact state between wires of the inner coil spring and the outer coil spring is set in an extended state of the multi-structured flexible body in accordance with a spacing between the one-side receiving member and an other-side receiving member on the device side.