In a deformable structure, connecting parts each of which has a base part are arranged longitudinally so that adjacent connecting parts are connected to each other. Respective first axes of the adjacent connecting parts are inclined to each other in a state that a spacer on one of the two adjacent base parts comes into contact with the other base part. When an external force is exerted on the deformable structure, the spacers restrain the deformable structure from being further curved into a radius of curvature smaller than a predetermined allowable radius of curvature. Most of the external force exerted on the deformable structure is born by the base parts and the spacers so that only a low force acts on the connecting parts. Thus the connecting parts do not break easily so that the deformable structure has a high strength.