Disclosed is a shock absorber which includes a shock transmission part having a lower end integrally coupled with a non-rotation wheel shaft of a tire and an upper end extending upward, a lever that is in contact with the impact transmission part at its one end and has a support pin at its center, and a shock attenuating part connected to the other end of the shock transmission part to attenuate impact applied to the lever through the shock transmission part during vertical movement of a vehicle. Therefore, an impact press point is moved to a center support pin of the lever as impact from thetire of the vehicle to a spring is increased. As a result, a spring constant is increased in proportion to movement of the pressing contact point, namely, by setting a small spring constant to the small impact, and a large spring constant to the large impact. Accordingly, although a smoother spring than a conventional spring is used, it is possible to appropriately deal with the impact amount fromthe tire in real time to offer both ride comfort and safety to a passenger, and a designer can obtain a desired magnitude of repulsive force within a preset impact range through inclination adjustment of a curved surface of the impact transmission part.