A folding mechanism is provided in which a rotor substantially tubelike is arranged between the stationary body and movable body; cams with given gaps are arranged at both ends of the rotor and on the facing surfaces of the stationary body and movable body; and a lubricating layer is formed between the outer circumference of the stationary shaft and the inner circumference of the rotor. The simple makeup implements a folding mechanism with a low impact when opening and reliable opening/closing operation.